1. Cylinder 2,3. Cover end, 4. Main bearing 5,Hollow shaft 6. pinion 7. Big gear ring, 8 mineral feeding device, 9. Cone shape inner cover 10. Bearing liner cover 11. Inspection hole.
The overflow ball mill has relatively simple structure--the advantage of no grate fence, high fineness in grinding, and less ball loading etc. Widely used in the second segment or place of comparably finer product.
When the motor drive the pinion and the big gear rotating, the material will get into the cylinder from the left end through the hollow shaft neck from the material feeding device. The cylinder are loaded certain weight of ball as the grinding media. The material get crushed under the ball function and discharged from the hollow shaft in the material feeding end. As the grinded material get discharged by overflow from the neck, the mill is called overflow type ball mill, a widely used ball mill.
The structure of overflow type is basically the same with the grate one, only with no material discharging grate in the cylinder outlet end. Besides, it has reverse screw blade on the surface of the hollow shaft inner liner cover. It can return the small ball in the slurry and overflowed rough ore back to the mill. As the grinded material get flowed freely from the hollow shaft neck, the slurry level must be higher than the lowest mother line level of the discharging shaft neck. Therefore, it is called high surface slurry mill sometimes. It is of simple structure and easy to maintain. And as it has fine product, it is usually used in grinding the fine ore, that is the size less than 0.2mm or the second segment in the two continuous stages.
| Model | Loading weight (ton/time) | Rotate speed (r/min) | Power (kw) | Liner material |
| 900×1200 | 0.2 | 38.5 | 5.5 | Ceramics, silica, rubber and metal (the liner material and grinding materials determine the power) |
| 1300×1500 | 0.5 | 33 | 7.5 | |
| 1500×1800 | 1.2 | 28.5 | 11 | |
| 1800×2000 | 1.5 | 24 | 15 | |
| 2600×2800 | 5 | 16.5 | 37 | |
| 3000×3800 | 10 | 14.5 | 55 | |
| 3200×4600 | 15 | 13.5 | 75 | |
| 3400×6600 | 18 | 13 | 135 |