Why Tube Axial Fan?
- September 22, 2019
- Alfa Fans
The axial design uses axial forces to achieve the movement of the air or gas,
spinning a central hub with blades extending radially from its outer diameter.
The fluid is moved parallel to the fan wheel's shaft, or axis of rotation. The axial fan wheel is often contained
within a short section of cylindrical ductwork, to which inlet and outlet ducting can be connected.
Axial fan types have fan wheels with diameters that usually
range from less than a foot (0.3 meters) to over 30 feet (9 m), although axial cooling tower
fan wheels may exceed 82 feet (25 m) in diameter.
In general, axial fans are used where the principal requirement is for a large volume of
flow, and the centrifugal design where both flow and higher pressures are required.These are axial fan units with fan wheels located in cylindrical tubes, without inlet or outlet dampers.Axial Fans are suitable for large quantities of air at low pressures while producing very little noise.Axial Fans have the advantages of lower price, Shorter Ducts, reduced space requirements.
There are two types of axial fans:
Direct Driven Axial Fans
Direct driven or multi-stage fans suitable for vertical or horizontal mounting.By running two
long cased fans in series with contra-rotating impellers it is possible to achieve up to three
times the pressure of a single stage fan of equal diameter and speed. In this instance the
casing covers the entire length of the motor and impeller and an inspection door is provided.
Essentially for duct mounting where flanges are bolted back and front. The casing covers the
impeller track and a portion of the motor projects beyond the end of the flange.
Best installed at the end of a duct or on air conditioning equipment.
Belt Driven Axial Fans
Axial fans are suitable for large quantities of air at low pressures while
producing very little noise. These Fans have the following advantages when
compared with Centrifugal Fans: Belt driven axial fans are used in situations where it
is important that the motor is kept out of the airstream owing to type or temperature of the
gases/fumes involved. An additional advantage is the accessibility of the motor for easy
maintenance. Belt driven fans suitable for horizontal or vertical mounting.
Long cased, the casing covers the entire length of the impeller, shaft bearings
and belt pulleys positioned inside and the motor mounted outside. An inspection
door is provided for access. Fan is suitable for air, up to temperature of 70 C.
V - Belt drive arrangement for the temperature between 70 and 160 and are equipped with
special high temperature lubricated ball bearings. The dynamically balanced impeller of axial
flow fan is manufactured using mild steel and aluminum alloy.