The process
Gypsum is calcined in kettles or flash calciners and the plaster moved by air slides. The calciner exhaust carries fine gypsum dust at temperature, and air slide blowers aerate the plaster on the way to the silos and packers.
The gas at the fan
Clean air at elevated temperature from a dryer, oven or cooling duty. The selection is made at the hot density, with the shaft and bearings arranged for continuous hot running.
Selection for this duty
| Blade form | Backward curved or aerofoil for the best efficiency on clean gas |
| Material of construction | Mild steel |
| Drive and bearings | Direct coupled, shaft cooling disc, bearings in a pedestal outside the gas stream, allowance for thermal growth |
| Density at the fan | At about 250°C the gas density is close to 0.67 kg/m³, 56% 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 gypsum calcining plants
Air Slide Blower in other processes
Cement Preheater KilnsVertical Roller Raw MillsBall Mill Raw GrindingCement Grinding MillsCement Packing and DispatchAsh Handling SystemsPneumatic Conveying SystemsSilo Aeration and FluidisationGlass Batch Houses
Information needed to select or quote
- Duty point. Volume flow and static pressure at the fan inlet, with the gas density and temperature or the conditions to derive it.
- Operating conditions. Site altitude, normal operating temperature and continuous or intermittent duty.
- Gas stream. Dust loading and particle size, corrosive species, moisture, upset temperature and any tendency of the material to deposit on the impeller.
- Mechanical. Rotation viewed from the drive end, discharge orientation and motor power.