Axial Fan Blower

An Axial Flow fan or an Axial Fan Blower is a particle mover which uses an impeller to push gases, liquids or solids along the axis of the shaft that the impeller is mounted on. The difference between a blower and a fan is that a blower has resistance to overcome, while a fan’s main purpose is to generate air movement.

Axial fans are generally used more for ventilation purposes as opposed to a centrifugal fan that is used to generate higher pressures and increase flow. A fan moves air through a system for ventilation and gas movement purposes.

An impeller is a rotor which is designed to create low pressure and high pressure areas at each side of the blade to promote air movement. The impellers of a fan are usually made out of specially machined aluminum which is carefully and accurately balanced to promote efficiency and smooth operation. The housings are sometimes made from heavy steel or strong metals for rigidity.

Axial fans can be driven by direct drive, belt drive or variable drive. Direct drive consists of an electric motor connected to a shaft which runs to the hub of the impeller.

Belt drive is a popular application on engines that make use of their torque to turn the fan wheel while operating the engine.

Variable drives use couplings made of magnets or powered by hydraulics.

Axial Fans work by using the concept of pressure difference of a gas in a space. Where ever the lowest pressure is in a controlled space with a singular gas and there are no external forces acting up on it, the gas will compensate by flowing particles to that area and hence lower the overall pressure to compensate and develop a uniform pressure in the space. Axial Flow fans are good for applications such as Wind Tunnels, Domestic Ventilation, Industrial Ventilation and internal combustion engine radiators.

Axial Fan Blade Type

Axial fans either have fixed pitch blades or variable pitch blades. The fixed pitch blades have a fixed angle at which the blades stand while in operation. Variable pitch blades are able to vary the pitch of the blades on the impeller to change the amount of air flow or pressure forced into the system through a specific time.

Some Variable Pitch Axial fans can vary the pitch while in operation while others have to shut off the machine to manually change the pitch of the blades. These are called Variable Pitch on-the-fly Axial Fans and are useful in instances where the conditions vary greatly while the fan is in operation.

Axial Fan Dampers

An Axial fan can be fitted with dampers to vary the volume or pressure without changing the pitch of the blade. Dampers can also be used to direct the flow. Dampers have been a cost effective solution for many HVAC systems that require the conditions to change without obtaining an expensive variable pitch fan. Dampers open and close like a window or shutter.

Axial Fan Types

There are three types of Axial Flow Fans. These are the Impeller type, Tube-Axial and Vane-Axial. The Impeller type of axial fan is housed in a shell that runs close to the circumference of the impeller. Impeller Axial Flow fans are the simplest form and can be found many places. Some of its uses are as domestic fans, ventilation fans, radiator fans and reverse flow fans.

The Tube-Axial fan, like the kind Custom Fans of Australia supplies, is an axial impeller which is mounted in a tube to an aerodynamically created tunnel. Tube-Axial fans are good for flexible round duct ventilation and exhaustion applications. Circular ducts can be connected to the fan to assist in generating and maintaining the shape of the duct while promoting air flow or a forced pressure along the travel. These are usually used for heavy-duty applications in supermarkets, factories or large commercial areas.

The Vane-Axial fan generates high pressures due to strategically mounted stationary vanes within the passage way of the flow.

In conclusion, Axial Fan Blowers are very useful devices for generating ventilation while keeping the pressure as constant as possible.