The process
Large sheds shed heat through the ridge with roof extractors and draw fresh air through louvers or supply fans. Evaporative cooling is added where the process heat is high.
The gas at the fan
Ambient air carrying light dust from the surroundings, enough to settle on blades over months but not to erode them. Inlet screens and a wheel that sheds deposit are the usual precautions.
Selection for this duty
| Impeller | PAG or die-cast aluminium impeller for low power, fixed or variable pitch |
| Form | Tube axial for low pressure; vane axial where the pressure or the downstream distribution calls for it; bifurcated where the motor must be out of hot or contaminated air |
| Density at the fan | At about 35°C the gas density is close to 1.15 kg/m³, 95% 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. |
Supply, return and exhaust fans for heating, ventilation and air conditioning of plant and office space. Low pressure, so efficiency and noise govern. Client-stated blade types for the HVAC in general: Axial, backward inclined and forward curved.
Industries
Other fans in factory shed ventilation
HVAC in other processes
Pharmaceutical Clean RoomsGas Compressor StationsTobacco Primary ProcessingFood Ovens and FryersPaper Machine Dryer SectionsDyeing and Finishing HousesAutomotive Paint ShopsTyre Plant Mixing and Carbon Black HandlingTyre Curing PressesGenerator and Engine RoomsCar Parks and TunnelsNuclear Facility VentilationCold Rolling MillsRubber and Plastics CompoundingHospitals and LaboratoriesData Centres and Equipment RoomsSpinning MillsPharmaceutical Coating and GranulationJute Mills
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.