1. The feed is interrupted or the ratio changes suddenly. In the production, the flow rate of the grinding material is controlled by the batching microcomputer, but the jamming phenomenon occurs at each of the blanking rollers, and the interruption of the feeding or the sudden change of the ingredients is caused. Especially when the clay ratio is interrupted, the vibration of the vertical roller mill is often caused. In order to prevent this from happening, in the absence of good monitoring equipment, the batcher is required to work closely with the vertical roller mill operator. Once the batcher finds that the material is blocked or the belt scale shows zero, it is necessary to promptly eliminate the fault. Notify the mill or the central control room. When the material break time is within 1rain, the sudden vibration of the vertical roller mill will not be triggered.
2. Vertical grinding ventilation or sudden changes in negative pressure. The vertical roller mill uses the waste heat of the rotary kiln to dry the material in the mill. The process of the kiln system encounters sudden failures, such as high-temperature fan tripping, cyclone blockage or exhaust gas CO explosion, etc., which will cause sudden vibration of the vertical roller mill. Although this phenomenon is rare, the vibration caused by this is more harmful. Measures to effectively avoid this phenomenon are the addition of CO gas monitoring and equipment opening and parking interlocking devices.
3. Ingredded materials contain large stones. The material used in the cement plant adopts the first-stage crushing system. It is inevitable that the stones with ≥50ram inclusions in the limestone or clay enter the mill, especially when the amount of inclusion is large, which will cause short-term vibration during the crushing process in the vertical roller mill. Such vibration has little effect on the vertical grinding operation and can be avoided by technical modification and regular maintenance of the equipment of the crushing system.
4. material wearability changes. The high content of silica and alumina in limestone will change its grindability and make grinding difficult. If the feeding amount is not reduced synchronously or the pressure of the grinding roller cylinder is increased during the production operation, the material on the grinding disc will gradually increase as the material in the grinding material is reduced by the one-time grinding ability, and the material thrown to the air inlet ring is easily clogged. In the air duct, the ventilation resistance increases, forcing the negative pressure of the incoming airflow to decrease. When the human gas negative pressure ≤ 650Pa, the vertical roller mill will suddenly slag a large amount of slag and produce severe vibration.
5. The grinding roller has failed. After the grinding roller is difficult to rotate due to internal bearing damage, a large amount of slag is generated in the slag gate in the non-rotating direction, and the grinding roller in the rotating direction may suddenly vibrate. At this time, the operating current of the main motor will also suddenly increase. When this happens, stop immediately. Effective measures to prevent the damage of the grinding roller bearing are to strengthen the lubrication of the bearing and regularly check the oil quality in the grinding roller, improve the lubricating oil pipe diameter and the shaft end gas sealing structure, and prevent the dust from entering the bearing inside the bearing from the bearing through the cover. The unit has failed. The classifying device is mounted on the top of the vertical roller mill, and the change in the rotational speed serves to adjust the fineness of the product. When it does not turn due to failure and the resistance of the dust airflow suddenly decreases, the normal airflow trajectory changes in the grinding machine. A large number of particles with ≤imm particle size pass through the classifying device, and the thickness of the material layer on the grinding plate is seriously unevenly distributed. , causing sudden vibration of the vertical roller mill. The preventive measures are to strengthen the lubrication and regular maintenance of the equipment; pay attention to the observation record of the running current of the graded motor, and find that when the current increases or decreases, it is necessary to stop the inspection.
There are also differences in the causes of vertical roller mill vibrations for different types of vertical roller mills and production process conditions, material properties and mix ratios. As long as you pay attention to observation and summary, constantly improve the operation method, use the necessary instruments, instruments and network control to improve the equipment management level, it is possible to control the vertical roller mill vibration value within the appropriate range to ensure the smooth operation of the vertical roller mill and energy saving and high yield.