The process
Tunnel kilns for bricks and refractories need an exhaust fan on the preheat end, cooling air fans on the exit end that feed hot air to the dryer, and combustion air for the burners.
The gas at the fan
Kiln exhaust with light dust and fluorine or sulphur compounds from the body and glaze. Hot, mildly corrosive; stainless steel or coated construction on the wetted parts.
Selection for this duty
| Blade form | Backward inclined or backward curved; the residual dust does not justify a radial wheel |
| Material of construction | Stainless steel on all wetted parts, grade to suit the gas analysis |
| 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. |
Circulates or supplies air at elevated temperature to a dryer, oven or kiln. Selected at the hot density with the shaft and bearing arrangement built for continuous hot running. Client-stated blade types for the Hot Air Fan in general: Backward curved and backward inclined.
Industries
Other fans in brick and refractory kilns
Hot Air Fan in other processes
Hot Air GeneratorsBall Mill Raw GrindingCement Grinding MillsCement Plant Coal MillsGypsum Calcining PlantsSponge Iron Rotary KilnsSteel Reheating FurnacesHeat Treatment FurnacesForge ShopsAluminium Smelters and Cast HousesHot Dip Galvanising LinesGlass Melting FurnacesGlass Forming and Annealing LehrsCeramic Tunnel and Roller KilnsCeramic Body Spray DryersEffluent Treatment and Zero Liquid Discharge PlantsSolvent Recovery PlantsFertilizer Granulation PlantsFertilizer Rotary Dryers and CoolersFood and Dairy Spray DryersRotary DryersFluid Bed Dryers and CoolersBelt and Tray DryersTea Withering Troughs
Services on this fan
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.