Internal Structure of the Grid Ball Mill

The grid ball mill is mainly composed of shell, feeding device, discharge device, transmission device, bearing and lubricating system, this paper will makes a detailed discussion of each part.

The shell of grid ball mill is welded by thick steel plate and there are flanges welded in the ends of the shell and both flanges are closely connected with end covers. In the surface there are manholes which is convenient for changing the inner liner and maintenance. Wear resistant manganese steel liner is embedded inside the shell to protect the shell and lift the steel ball. Ball mill liner is divided into smooth one and not smooth one. Smooth liner is appropriate for fine grinding because the sliding of steel ball is bigger and the grinding strip effect is stronger. Not smooth liner can bring steel ball into a higher position and fall down and have strong agitation for steel ball and materials, so it is suitable for the coarse grinding.

The feeding device of the grid ball mill is generally divided into worm feeder, drum feeder, and drum scoop feeder. The worm feeder is for the second period of two stage grinding, drum feeder is used to open circuit grinding, and drum scoop feeder used in the first section of the closed-circuit grinding. There is journal inner sleeve whose inner surface is made of helical blades embedded in the jugular of the hollow shaft of the end of the ball mill feeding device.

The discharge part of the grid ball mill consists of components such as fan-shaped grid plates, trunnion covers, center plates and shaft sleeves. The size and arrangement of grid plate hole have great effect on ball mill processing capacity and product fineness. The hole should stop the steel balls and coarse particles discharging from the ball mill, and guarantee to discharge slurry that contains qualified particle. In order to avoid clogging particles, grate hole should be made into a trapezoidal size and gradually expanded to the discharge end.

Large grid ball mill adopts synchronous motor to drive the small gear through the coupling. The small gear is engaged with the outer surface of the shell, then the shell is rotated. Ball mill is characterized by low speed, high load and strong impact, so the main shaft is usually used sliding bearing. And according to the working characteristics of the mill, a lubricating system is installed in the ball mill.