How to discharge materials from dry rod mill?

The discharge process of the dry rod mill is the core link that determines the grinding efficiency and the quality of the finished product. Its technical implementation involves many factors such as mechanical structure design, material motion control and particle size adjustment. This article combines industrial practice and analyzes from three dimensions: discharge method, control technology and structural optimization.

1. Classification and selection of discharge methods

Dry rod mills mainly adopt two discharge modes: natural discharge and mechanical discharge. Natural discharge relies on the gravity of the material itself and the centrifugal force generated by the rotation of the cylinder to achieve discharge. It is suitable for materials with good fluidity and has the advantages of low energy consumption and simple maintenance. Mechanical discharge forces discharge through a screw conveyor or a push mechanism, which can solve the blockage problem of viscous materials or materials with high moisture content, and is suitable for scenes with high requirements for discharge continuity.

2. Particle size control and optimization of discharge structure

The discharge particle size directly affects the efficiency of subsequent processes. The dry rod mill can stabilize the finished product particle size within the range of 0.147-0.833mm by adding an adjustable screening device or a built-in fineness control device to the discharge port. Some high-end models adopt a double-layer grate plate structure, which can achieve graded discharging by adjusting the grate gap width (usually 3-7mm), effectively reducing over-crushing. The conical discharge grate at the end of the barrel and the blade combination design can improve the material passing efficiency and reduce the risk of accidental discharge of steel rods.

3. Coordination of power system and discharging efficiency

The stability of the discharging process is closely related to the equipment drive system. The dry rod mill drives the reducer through an asynchronous motor, and the small gear drives the large gear to realize the rotation of the barrel. Speed control is particularly critical: too high speed will cause the material to be discharged too early and insufficiently ground, while too low speed will reduce the output. Optimization practice shows that controlling the barrel speed at 60-75% of the critical speed (usually 12-18rpm) can balance the grinding time and discharging efficiency.