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 Air Swept Ball Mill |
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As indicated in the
flow sheet, this mill is fed at one end and the product is swept by passing large quantity of hot air through the mill. The grits get separated in the grit separator and the product is separated in cyclones and bag fitter. The grits are fed at the mill inlet again. Drying chamber can be provided before the grinding chamber. The grinding chamber is characterized by very low L/D ratios and coarse finished product.
The system for using for drying large quantity of moisture and consumes more power than the other systems due to pneumatic handling of the material. Therefore, it is ideally suitable for coal grinding applications in cement plants where drying is the prime requirement and quantity of coal required is relatively small as compared to the other materials ground in a cement plant. |
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| Air Swept Ball Mill : |
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1. |
Raw Coal Hopper |
2. |
Table Feeder |
3. |
Ball Mill |
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Grit Separator |
5. |
Cyclones |
6. |
Bag Filter |
7. |
Fan |
8. |
Cyclone |
9. |
Hot Air Fan |
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 Air Separators For Fines Separations |
| Dynamic Air Separators |
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Material is fed sideways on a spreader disc in the separating chamber. The spread material is divided into grits fines by a recirculating air current created by inbuilt fan fall on the inner cone and fines get separated from recirculating air by cyclonic action. Counter vanes with adjustable length are fitted above the spreader plate to control fineness of the fines. The fan, spreader disc and the counter vanes can be driven by a single drive.
If the fineness is to be varied without stopping the separator, separator fan is driven by a constant speed motor and the spreader disc and counter vanes are driven by a variable speed drive. By varying its speed, fineness can be infinitely adjusted. This separator is still preferred for coarse separation (90 micron size) due to lower specific power consumption, and can be used for raw material grinding applications.
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| High Efficiency Separators |
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Material is fed at the centre of a distribution plate installed on top of a cage rotor. The air flow created by an external fan enters horizontally and flows through a curtain of the material falling from the distribution plate. Heavier particles get separated under the effect of gravity and centrifugal force. Fines get carried away with the air by drag force. The dust laden air leaves separator and fines get separated in cyclones arranged outside the separator. Clean air can be recirculated or dedusted. The cage rotor is driven by a variable speed drive to facilitate on line fineness control.
The separator gives very good control on fines separation and avoids recirculation of fines and hence improves the capacity of grinding system and also helps in improving the product quality due to close particle size distribution. |
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Following features are unique with this separator –
- External highly efficient fan for air recirculation.
- External, efficient separating cyclones for fines separation.
- Distribution is on the top of the selection zone.
- Cylindrical selection zone gives longer time for fines separation.
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Cement Division
