The process
The dryer hood takes in heated air and exhausts the saturated air from the drying cylinders through heat recovery. Supply and exhaust fans handle warm, humid, fibre-laden air in stainless steel, with mist elimination on the exhaust.
The gas at the fan
Dryer hood exhaust is saturated, warm and carries fibre and chemical traces. Stainless steel construction, drainage and a design that does not trap fibre.
Selection for this duty
| Blade form | Backward curved or aerofoil for the best efficiency on clean gas |
| Material of construction | Stainless steel on all wetted parts, grade to suit the gas analysis |
| Drive and bearings | Direct coupled or belt driven; belt drive where the duty point may need tuning at site |
| Also specified | Casing drain at the lowest point |
| 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. |
Sits at the outlet of a boiler, kiln or furnace and draws the flue gas through the plant to the stack. It handles hot, dust-laden gas at large volume, so it is sized at the hot condition and checked at cold start. Client-stated blade types for the ID Fan in general: Backward curved, backward inclined and radial tipped.
Industries
Other fans in paper machine dryer sections
ID Fan in other processes
Bagasse Fired BoilersRice Husk Fired BoilersAFBC BoilersCFBC BoilersPulverised Coal Fired BoilersOil and Gas Fired BoilersWaste Heat Recovery BoilersBiomass Fired BoilersThermic Fluid HeatersHot Air GeneratorsRotary Lime KilnsVertical Shaft Lime KilnsGypsum Calcining PlantsSponge Iron Rotary KilnsBlast Furnace Hot Blast StovesSinter PlantsCoke Oven BatteriesElectric Arc Furnace SteelmakingSteel Reheating FurnacesHeat Treatment FurnacesFerro Alloy Submerged Arc FurnacesCopper and Zinc SmeltingGlass Melting FurnacesCeramic Tunnel and Roller Kilns
Services on this fan
Fan and System Performance TestingFan Energy AuditRetrofit of Low Efficiency FansRotor Replacement and Performance EnhancementDynamic Balancing and Vibration AnalysisCondition Monitoring and TroubleshootingInstallation, Commissioning and After-sales Support
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.