How to reduce the failure of bucket elevator in the application of raw meal vertical mill circulation technology

RMR57/28/555 vertical mill is used for raw meal preparation in the production line. During the trial production period, the current of the circulating bucket elevator is often too high due to improper operation, resulting in the bucket elevator being crushed and the mill tripping, which not only increases the workload of the on-site personnel, but also affects Production. After continuous summary and practice by operators, a set of effective central control treatment measures have been formed, which effectively avoids the occurrence of such phenomena.

The problematic outer circulation bucket elevator model is: NSE300, the conveying capacity is 450t/h, the motor power is 75kW, the rated current is 140A, and the alarm value is 150A. In actual production, the grinding conditions are often changed due to sudden changes in raw materials and unstable incoming materials, resulting in a large amount of external circulating materials, resulting in high hoist current. In the initial stage of production, the usual operating method is to rapidly reduce the feed volume, increase the grinding pressure, and appropriately reduce the speed of the powder separator, so that as much fine powder as possible is discharged out of the mill with the gas, reducing the amount of material in the mill, thereby reducing the external The amount of circulating materials. However, in actual operation, it was found that the adjustment time of this operation method was too long, and a large amount of material was too late to be discharged from the mill, and eventually the circulating bucket elevator was crushed to death. Since the elevator and the mill are in a chain relationship, the mill will also stop after the elevator trips.

Improvement measures Through exploration and practice, it is found that when the circulating bucket elevator current reaches the critical value of 140A, or even reaches the alarm value of 150A, the following measures can be taken quickly to effectively avoid the crushing of the circulating bucket elevator.

① Stop entering the grinding belt quickly, and prohibit materials from entering the grinding. ②Rapidly reduce the grinding pressure, so that the material temporarily forms a thicker layer on the grinding disc, so that the material for the external circulation bucket elevator is drastically reduced. ③Appropriately reduce the speed of the separator so that the fine powder in the mill is discharged from the mill as soon as possible (the speed of the separator should not be too low to prevent the raw material from being too fine). ④When the current of the circulating bucket elevator has a downward trend and drops to about 140A, the material volume can be reduced to 200~300t/h, the feeding belt can be turned on, the grinding condition can be adjusted to a stable state, and then normal operation can be carried out.

Practice has proved that this method of operation is simple and easy to implement, can quickly reduce the amount of external circulating materials in a short time, and effectively avoid the phenomenon of the circulating bucket elevator being crushed and the mill tripping due to the large amount of external circulating materials. It plays a vital role in the long-term operation of the mill, thus ensuring the normal feeding of the rotary kiln and greatly reducing the power consumption of the raw meal grinding system.