When vertical roller mill is broken and running with load, the locking failure is caused by the pressure loss of the hydraulic station, and the adjusting sleeve will rotate with vertical roller mill. If the operator does not find and deal with it in time, it will cause the adjusting sleeve to be stuck, which will lead to the vertical roller mill and shutdown.

The causes of adjusting sleeve sticking may also be poor thread lubrication, wear of adjusting cap seal or dust cover seal, scratch of adjusting sleeve and support sleeve thread, or vertical roller mill, long time overload work, etc.

Cement water demand in vertical roller mill processing has attracted the attention of cement users, especially in the commodity concrete developed areas; more and more users of cement put forward higher and higher requirements for water demand. Concrete producers want to choose cement with small water demand, which will affects the competitiveness and price of cement products, then affecting the cost and benefit of cement producers.

There are many factors that affect the cement water demand in vertical roller mill processing; one of them is grinding process. In other words, different grinding process produced cement; the water demand is not the same. If you want to improve the efficiency of the grinding system, no matter what kind advanced grinding process, we must consider the appropriate water demand of cement technology. Otherwise, we must find a balance between the grinding efficiency, the grinding cost and the water requirement.

At present, there are broken line shaped and circular arc shaped ultrafine vertical mill in the market. The angle of each stage of impact plate has a great influence on the effective crushing force of the material impacting the impact plate, and also has a great influence on the impact and shear crushing effect of the material.

The broken line impact plate has a simple structure, but it can not guarantee the most effective impact crushing of ore. therefore, when purchasing and debugging the impact plate, we must pay attention to the angle of the impact plate, so that when the material collides with the impact plate, it can be perpendicular to the impact plate, so as to improve the production capacity of the impact plate.

The arc-shaped impact plate is commonly used in involute linear structure. The characteristics of this structure are that at each point of the impact plate, the ore is impacted in the vertical direction, resulting in higher crushing efficiency and higher production capacity.

Some concentrators did not adjust the size of the opening of the classifier during the equipment installation, and the operator did not pay attention to it during the vertical roller mill operation.

which would also affect the grinding operation invisibly. The lower opening of the classifier is low, and the ore sedimentation area is large, so the amount of returned sand is increased, and the fineness of grinding is relatively fine.

The lower opening of the classifier is large, the ore sedimentation area is large, and the water flow is relatively smooth, so the amount of returned sand is increased, and the fineness of grinding is relatively fine. In the same way, when the opening on the classifier is low and large, the amount of returned sand will increase and the fineness of grinding will be relatively finer. Otherwise, on the contrary, the grinding fineness becomes coarser.

1. Vertical Roller Mill Does Not Produce Powder Or Less

The causes are as follows: 1) the discharge valve (powder locking device) is not closed tightly, and the outside air and dust are sucked back; 2) The air duct of the main engine is blocked; 3) Blade wear, resulting in too little or unable to shovel material; 4) There is serious air leakage at the joint of pipe and flange.

Solutions: 1) repair or seal the discharge valve; 2) Remove the blockage; 3) Check the blade wear and replace it; 4) Carefully check and re seal the air leakage.

2. The oil tank and transmission are hot

Causes: 1) the viscosity of engine oil is too thick; 2) The direction of the analyzer is not right.

Solutions: 1) check whether the viscosity of engine oil meets the requirements; 2) Adjust the running direction of the analyzer.

 

Periodically inspect the oil quality and detect the content of metal particles in the oil sample to determine the bearing damage. At the same time, keep the lubricating oil clean, and judge whether to replace the lubricating oil according to the oil quality and the replacement interval of the oil filter.

Pay attention to the heating and cooling operation of the mill. Most manufacturers do not pay attention to the heating and cooling operations of ultrafine vertical mills, and fail to realize that reasonable heating and cooling operations can prolong the service life of key large bearings and wear parts.

Reasonable heating rate can heat the roller sleeve, liner plate and bearing uniformly, thereby prolonging the service life of the liner plate, roller sleeve and key bearing. Among the spare parts of the mill, the price of these key parts is relatively expensive, and any one of them is damaged. Will directly affect the operation cycle of the mill.

Due to the importance of the roller lubrication system to the bearing of the vertical mill, a simple method can be used to quickly diagnose whether the roller bearing is faulty in normal production:

One is to observe the oil condition in the grinding roll on site, or to determine whether the bearing of the grinding roll is damaged by detecting the content of metal particles in the oil sample. If the content of metal particles in the oil sample is high, the bearing has been seriously damaged.

The second is to observe the oil return temperature of the ultrafine vertical mill. If the oil return temperature of a certain ultrafine vertical mill rises and the return oil temperature of other ultrafine vertical mills is normal, it indicates that the bearing of the ultrafine vertical mill is damaged.

Metal objects are mixed into the grinding chamber of the main engine of ultrafine vertical mill

Since the central axis of the main machine rotates very fast and the metal objects are very hard, after being shoveled up by the shovel, they will collide everywhere in the main machine's grinding chamber, causing the main machine to vibrate, and the metal objects need to be cleaned.

It should be noted that the metal objects may be brought in from the raw materials, or the internal parts of the ultrafine vertical mill may fall off and fall in, such as screws or bearing balls.

The couplings of the main engine and the reducer are different

The direct power of the main engine and the reducer is transmitted through the coupling. After the machine is turned on, the main machine and the reducer will produce vibration and noise because the two couplings have different shafts. Therefore, the coupling must be calibrated before starting the machine.

The setting range of tension force should be reasonably determined. If the setting range of grinding pressure is narrow, it will not only weaken the buffer capacity of ultrafine vertical mill in hydraulic system, but also make the high-pressure oil pump of hydraulic station start and stop frequently in a short time, which will cause the high-pressure motor to burn down in serious cases. Generally, reasonable grinding pressure parameters should be determined according to the abradability of materials.

Check and clean the hydraulic valve (and pressure relief valve). The hydraulic valve belongs to the precise parts, and the pressure relief will be caused once there is debris in the valve port.

In a word, it is one of the main ways to reduce system failure and improve grinding efficiency of mill to use and maintain hydraulic system correctly and keep hydraulic system running well.

Nitrogen must be used for charging the accumulator. It is strictly forbidden to replace it with other gases. Before filling nitrogen, the remaining air in the ultrafine vertical mill shall be removed. Otherwise, the mixture of air and nitrogen will easily cause the burst of ling. According to relevant standards, the general inflation pressure is controlled in 60% - 70% of the system working pressure.

During normal production, it is required to check nitrogen of accumulator once a week. When the vertical mill is inflated, the ling expands at the upper part with large diameter and thin wall, then expands to the lower part, pushes the ling outward to the side wall of the shell, and the vertical mill is filled with the whole container, and the friction between the outer wall of the ling and the inner wall of the shell is large.

Therefore, during installation, the hydraulic oil shall be applied to the outer wall and inner wall of the shell of the ling to reduce the friction between the ling and the inner wall of the shell, and protect the ling. Before removing the accumulator, the pressure oil in the accumulator must be removed, and then the nitrogen in the leather bag can be released by the filling tool before the other parts can be removed.