Range
0.3 to 70 m³/sCapacity
3 to 75 mmWCStatic pressure
Fixed or variable pitchImpeller options
Axial fans are designed for optimum efficiency and low noise levels. Depending on the medium of air and the temperature they are offered in three drive forms.
Drive forms
Direct drive
Impeller mounted on the motor shaft inside the casing. The simplest and most compact form for clean air.
Belt drive
Motor mounted outside the casing on a pedestal. Fan speed set by the pulley ratio; motor kept out of the airstream.
Bifurcated
The casing is split so the motor sits in a chamber outside the gas path. Used for hot or contaminated air.
Impellers
| Rotor materials | Pressure die-cast (PDC) aluminium, nylon and PAG (polyamide glass fibre). Rotors in stainless steel and mild steel can also be offered. |
| Pitch | Fixed pitch or variable pitch. Variable pitch impellers allow the capacity to be varied by changing the blade pitch angle. |
| PAG impellers | Widely recommended for energy conservation over conventional heavy aluminium impellers. |
| Housing | Fabricated from mild steel or stainless steel. |
Applications
- Ventilation in all forms. Supply air or exhaust air for factory sheds, process halls and plant rooms, as wall fans, roof extractors, ducted tube axial or vane axial units.
- Drier application. Air circulation and exhaust on tea withering troughs, belt and tray dryers and similar low pressure drying duties, with the impeller material chosen for the temperature.
| Application | What it does | Type usually selected |
|---|---|---|
| Shell Cooling Fan | Blows ambient air onto the rotary kiln shell in the burning zone to protect the refractory and the shell steel. A row of axial fans along the kiln, each covering one length of shell. | Axial |
| HVAC | Supply, return and exhaust fans for heating, ventilation and air conditioning of plant and office space. Low pressure, so efficiency and noise govern. | Axial, backward inclined and forward curved |
| Trough Fan | Blows a large volume of ambient or warmed air through the bed of green leaf on a withering trough. Low pressure, long running hours, and a fan that must be easy to clean. | Axial |
Axial fan forms
| Form | Description | |
|---|---|---|
| Tube axial |  | Axial impeller in a cylindrical housing that fits closely to the blade tips. Low to medium pressure ducted duties. |
| Vane axial |  | Adds straightening vanes behind the impeller, which raise the pressure capability and the efficiency. Good downstream air distribution. |
By process
The same duty, selected for the gas of each process.
Industries
SugarCement & LimeChemical & PharmaDriersTobaccoTeaFood ProcessingAutomobileDyeing IndustriesTyreNuclear
Testing and balancing
| Performance testing | IS 4894, BS 848 Part I, or as per customer standards |
| Rotor balancing | Static and dynamic balancing to grade G 6.3 or G 2.5 as per ISO 21940-11 |
| Records supplied | Material of construction certificates, static and dynamic balancing records, and test reports as per customer standards |
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.