With more than 20 years of experience in the preparation and characterization of mining machine, Zenith is the world-market leader in milling and crushing machine manufacturing technology. We develop instruments whose high-quality components are designed for perfect interaction. Thus, they not only guarantee representative and reproducible results for grinding and particle analysis but also allow for easy and safe operation. Zenith not only provides the high quality coal milling plant but also offers the coal mill accessories to customers.
Coal mill accessories
Depending on the size of coal mill, its accessories shell is supported at the periphery by two, four or six slide shoes. The self-aligning support of the slide shoes compensates any slide ring wobbling and eccentricity caused by mill sag, thermal distortion and manufacturing tolerances. Hydrodynamic or hydrostatic lubrication systems can be used for this type of bearing.
The mill can be lifted and positioned by hydraulic jacks installed in the base of the bearing to compensate for foundation settlements and allow replacement of bearing shoes without complicated supporting of the mill shell. It is also possible to install load cells in the base of the bearing in order to determine the weight of the mill.
Well-proven seals keep dirt and water out of the bearing housing and reliably prevent oil leaks. The mill shell is a welded structure without heavy and complicated end disc castings. The straight end disc design provides significant advantages: simple liner plate shape, quick replacement of the mill lining and free design of the mill inlet and outlet to suit process requirements instead of structural constraints.
The ring motor transmits the motor torque to the coal mill accessories shell through a magnetic gap. As no wear and tear occurs, high availability and long drive service life are assured. The variable speed capability comes with the drive as an inherent feature. Due to the investment cost the ring motor drive is usually applied for drive powers above 10 MW. Shell-supported grinding mills offer special benefits to ring motor drives:
- Shell-supported grinding mills offer a high system stability to withstand the magnetic forces developed by the motor and which have to be accepted by the mill structure;
- The hydraulic jack incorporated into the slide shoe support enables easy centring of motor stator and motor poles, which are attached to the coal mill accessories shell.