Although there are some similarities between centrifugal fans and axial fans, there are also distinct differences. Regardless, both types of fans are used for industrial applications.
Centrifugal fans, also referred to as blowers and squirrel cage fans because they resemble a hamster wheel, were invented in 1832 by Lt. Gen. Alexander Sablukov, a military engineer with the Empire Imperial Russian Army. This type of fan is capable of moving air, as well as other gasses. The speed of the airstream increases thanks to rotating impellers, which are a series of blades.
The various types include forward curved, backward inclined, radial, airfoil, radial tip, and inline. Two specific characteristics of the centrifugal fan are high pressure and low flow rate, with flow perpendicular to the blower axis. Fans designed with paddle impellers are ideal whenever debris passes through the system, thereby preventing clogs. For fans with blades that curve backward, the volume of air produced is less than with axial fans while the amount of pressure generated is more significant.
With this type of industrial fan, there are multistate units that produce even higher pressure. For the best airflow and pressure, fans with forward curved blades are recommended, although they do require additional motor power. The centrifugal fan is ideal for process heating and cooling, boiler combustion air, electronic cooling, and air handling units.
Axial fans also have different shaped blades, such as paddle, sickle, variable pitch, and aerofoil. For low pressures and relatively high flow rates with the flow being parallel to the fan’s axis, this is the perfect choice. In addition, axial fans have a low power input.
Typically, axial fans are the better choice for cooling applications or simple extraction with low system resistance. For example, this would include moving air from a single large space to another area. Axial fans are also commonly used for condenser cooling in refrigeration and desk fans.
Named for the direction of airflow created, axial fans have blades that rotate around the axis. Air is drawn in parallel to the axis, which then forces air out going the same direction. Based on the design, these fans can produce a large volume of airflow at a low pressure. Interestingly, the first fans powered by electricity in the late 19th century were axial fans.
The Bottom Line
Because centrifugal fans create high pressure, they work great for high-pressure applications, including air conditioning and drying systems. A unique design aspect is that all of the moving parts are enclosed. These fans also have particulate reduction properties, making them a superior choice for filtration and air pollution systems.
Because axial fans create high-volume but low-pressure airflow, these fans work best for general purpose applications. These fans are superior in moving air from one location to another, as well as cooling both large and small spaces. Due to the definite difference between centrifugal fans and axial fans, it is important to choose the fan according to the application.