The process
Small two-chamber incinerators for hospital waste use a venturi or packed bed scrubber and an ID fan in stainless steel or FRP. Volumes are small and the duty is intermittent, so the fan is built for corrosion rather than for size.
The gas at the fan
Flue gas after the quench and scrubber is wet, acidic and still carries fine dust. The fan is in stainless steel or lined construction, with a shaft seal and drains, sized at the saturated density.
Selection for this duty
| Blade form | Radial tipped, or backward inclined where the fan sits after the collector |
| Material of construction | Stainless steel on all wetted parts, grade to suit the gas analysis |
| Drive and bearings | Direct coupled or belt driven with a shaft cooling disc and bearings outside the casing |
| Also specified | Casing drain at the lowest point |
| 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. |
Feeds a burner with air at the pressure the burner register needs. Sized for the burner turndown range, and often fitted with an inlet silencer. Client-stated blade types for the Combustion Air Blower in general: Backward curved and radial tipped.
Industries
Other fans in biomedical waste incinerators
Combustion Air Blower in other processes
Bagasse Fired BoilersRice Husk Fired BoilersAFBC BoilersCFBC BoilersPulverised Coal Fired BoilersOil and Gas Fired BoilersBiomass Fired BoilersThermic Fluid HeatersHot Air GeneratorsRotary Lime KilnsVertical Shaft Lime KilnsSponge Iron Rotary KilnsBlast Furnace Hot Blast StovesSinter PlantsCoke Oven BatteriesSteel Reheating FurnacesHeat Treatment FurnacesForge ShopsFerro Alloy Submerged Arc FurnacesAluminium Smelters and Cast HousesIron and Non-ferrous FoundriesHot Dip Galvanising LinesGlass Melting FurnacesCeramic Tunnel and Roller Kilns
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.