Air Slide Blower for Cement Grinding Mills

The process

Cement grinding in ball mills or vertical mills needs a vent fan to carry heat and fines out of the mill, a separator fan where the circuit has one, and air slide blowers to move the product to the silos. Cement dust is fine and abrasive, and the fans sit after bag filters.

The gas at the fan

Hot gas that has dried the raw meal and now carries the fine product toward the separator and collector. Very heavy fine dust loading; the impeller is built for wear and balanced to tolerate build-up.

Selection for this duty

Blade form	Radial tipped with wear liners, or straight radial where the dust is coarse
Material of construction	Mild steel with replaceable wear liners on the blades and the scroll at the cut-off
Drive and bearings	Direct coupled or belt driven; belt drive where the duty point may need tuning at site
Also specified	Hard facing or liners on the blade pressure face
Density at the fan	At about 90°C the gas density is close to 0.97 kg/m³, 81% of standard air. Pressure developed and power drawn fall in the same ratio, so the selection is made at this density and the motor is checked at cold start.

Supplies low pressure aeration air to the fabric of an air slide, fluidising cement, raw meal or gypsum so it flows down the slide. Client-stated blade types for the Air Slide Blower in general: Backward curved and radial tipped.

Industries

Other fans in cement grinding mills

Air Slide Blower in other processes

Information needed to select or quote

1. Duty point. Volume flow and static pressure at the fan inlet, with the gas density and temperature or the conditions to derive it.
2. Operating conditions. Site altitude, normal operating temperature and continuous or intermittent duty.
3. Gas stream. Dust loading and particle size, corrosive species, moisture, upset temperature and any tendency of the material to deposit on the impeller.
4. Mechanical. Rotation viewed from the drive end, discharge orientation and motor power.