Explained: Regenerative vs Centrifugal Blowers

In industrial operations, both regenerative and centrifugal blowers are commonly utilized. The two types of blowers may appear identical on the surface, and it can be difficult to get clear information about the distinctions between the two types of blowers and why one would be preferred over the other.

First, let's look at what the two types of blowers have in common. Both versions use an impeller on a spinning shaft to propel air. Air enters the intake and is focussed as it travels with the impeller before being expelled as linear flow at the output. This is where the parallels stop.

How can you tell them apart?

The structural differences between centrifugal and regenerative blowers allow them to be distinguished visually. The intake and outlet of a centrifugal blower are perpendicular, with the inlet delivering air into the impeller's center and the exit tangential to the impeller's spin. The entrance and exit of a regenerative blower are parallel and perpendicular to the spinning of the impeller.

What is the practical distinction?

Blower Regent

The impeller and impeller housing of the two blowers are intended for various applications. Air enters centrifugal blowers through the center of a revolving impeller with a number of fixed vanes.

Centrifugal blowers, as the name indicates, move air by centrifugal action. Air is driven to the perimeter of the impeller and housing, where it is released as a continuous stream through the outlet. The resulting negative pressure at the center hub sucks in additional air. The vanes function essentially as paddles, pushing large quantities of air to the exit. Although no substantial pressure is generated during this operation, centrifugal blowers may be employed to transport enormous amounts of air.

As the impeller drives the air around the ring in regenerative blowers, centrifugal forces cause the air trapped between the revolving impeller vanes to travel towards the blower casing.

The air flow is then driven to the base of a subsequent impeller vane for recirculation. This circular flow, along with the impeller movement, enables air to spiral through a regenerative blower (see image), resulting in air that is constantly accelerated. Regenerative blowers may generate high pressure due to the "regeneration" of air with each round.

Centrifugal blowers are typically low pressure, high flow blowers, whereas regenerative blowers are high pressure, low flow blowers. These essential properties influence the sorts of applications to which they are best suited.

What should be used where?

Centrifugal blowers are used in situations where a significant amount of air is required to fill an area, such as heating a furnace with hot air. Because high quantities of air are necessary to achieve optimal air velocity out of air blades, blow-off applications are often better suited to centrifugal blowers.

Regenerative blowers can provide adequate pressure to overcome air flow limits in a process system, such as when a nozzle is required to restrict air flow from a large to a smaller cross section. The pressure of a regenerative blower will be advantageous if the air must traverse a suboptimal course with abrupt bends or a tortuous route.