The process
The arc furnace fume system takes hot primary fume from the fourth hole through a drop-out box and cooler, and secondary fume from the canopy hood, into a large bag filter. The main fume fan is a large volume duty at moderate temperature after the filter, with dampers balancing primary and secondary flow.
The gas at the fan
Fume from arc, induction or reverberatory furnaces, hot and carrying fine metallic oxide dust. Temperature is handled by dilution air or a cooler ahead of the filter, and the fan sits on the clean side where possible.
Selection for this duty
| Blade form | Radial tipped, or backward inclined where the fan sits after the collector |
| 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 with a shaft cooling disc and bearings outside the casing |
| Also specified | Hard facing or liners on the blade pressure face |
| Density at the fan | At about 200°C the gas density is close to 0.75 kg/m³, 62% 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. |
Injects ambient air into a hot flue gas stream to bring it down to a temperature the downstream bag filter or fan can accept. Client-stated blade types for the Dilution Air Blower in general: Backward curved.
Industries
Other fans in electric arc furnace steelmaking
Dilution Air Blower in other processes
Bagasse Fired BoilersWaste Heat Recovery BoilersBiomass Fired BoilersHot Air GeneratorsRotary Lime KilnsSponge Iron Rotary KilnsSteel Reheating FurnacesFerro Alloy Submerged Arc FurnacesGlass Melting FurnacesWaste IncineratorsBiomedical Waste IncineratorsCrematoriaDistillery Spent Wash Incineration BoilersLead Smelting and Battery Recycling
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.