The material blockage is one of the problems encountered by many crushers. Recently, I learned that a cement plant’s rotary breaker also encountered this problem. How did it solve it? Why not come and have a look!

Customer case

A customer’s cement plant limestone coarse crushing equipment used a gyratory crusher. During the first few months of trial production, the crusher was blocked for more than 4 hours every day on average. A lot of time was wasted during shutdown and maintenance, which seriously affected production efficiency and caused Lost.

After investigation, it was found that the main reason for the material blocking and stopping was that too much material accumulated in the lower cavity of the crusher could not be discharged, and the moving cone was resisted, causing the motor to overload and stop. There are usually two situations that cause jumps and stops.

(1) The output of the crusher is high, and the plate conveyor is too late to pull it away.

(2) The downstream equipment jumps and stops, and the crusher continues to crush. Once this happens, it takes time and effort to clean up all the materials in the crushing cavity to continue the machine. Generally, it takes at least 3 to 4 hours to complete.

To prevent material jams, various solutions have been adopted, and finally, the use of sound and light (alarm and light) indicators directly guide the material dumping, and the effect is very good.

Specific implementation steps

Because the operating current of the heavy-duty plate conveyor under the crusher has a good correlation with the amount of material in the lower cavity, and every time the material in the lower cavity causes the crusher to trip, the current of the plate conveyor exceeds a fixed value. The peak value (38A), and the no-load current is also a fixed value (18A). Therefore, a solution was formulated according to the current characteristics of the slat conveyor.

That is, install an electric bell and alarm flashing light at the crusher’s discharge port, which is directly connected to the relay in the electrical cabinet. When the plate conveyor reaches a set current value (such as 33A), the relay is closed, the alarm light starts to flash, and the electric bell also rang. If the downstream equipment trips and stops, when the current of the slat conveyor is zero, the sound and light alarm will also prompt. After receiving the alarm, the mine truck driver will stop dumping materials to prevent material jams.

The alarm current value of the slat conveyor should be set appropriately, not too low or too high. If the crushing cavity is too low, the material will be cut off frequently and rocks will hit the slab conveyor; if the setting is too high, the volume of the lower cavity will be large, and the buffer space will be insufficient. If the downstream equipment fails, it will easily cause the crusher to block the material. The practice has proved that the 33A setting value not only guarantees the continuous and stable discharge of the crusher but also leaves enough buffer space for the lower cavity of the crusher, which can effectively prevent material blockage.

The method is simple, reliable, and low-cost. Since its implementation, the crusher has never been blocked again, and at the same time, it has reduced the labor burden of workers and improved the production efficiency of the crusher.