About Regenerative Blowers

Several descriptive names have been used for “regenerative” blowers by different manufacturers, which may include “side channel”, “vortex”, or “ring compressors”. These are basic descriptions of the blowers based on the dynamic motion of the air stream inside the blower housing as it turns in a spiraling effect. As the impeller blades pass the inlet port in the blower, a low pressure area is generated that draws air/gas into the voids between the impeller blades. The air captured in these voids is thrown by centrifugal force from the base of the impeller to the housing perimeter, then is returned by side channels back to the root of the impeller. The shape of the housing side channels creates a spiraling effect in the air, and the process is repeated. With each rotation of the impeller, many complete air movement cycles take place creating a vortex, and pressure is regenerated each time the air is centrifugally thrown to the perimeter of the housing until it is discharged at the outlet port of the blower.

Regenerative Blowers

These blowers can be used for pressure service or vacuum service.  The term “ring compressor” is an apt description for these blowers as they operate based on compressor laws, and not fan laws. Power consumption (or work) generated based on fan laws is relevant to volume of air, or weight of the air/gas that must be moved. Higher volumes result in greater work load, and result in higher power consumption.  As pressure increases with centrifugal blowers, there is less capability to entrain air at the inlet resulting in decreased volume, resulting in lower power consumption or work being performed. Based on “compressor laws”, higher pressures or vacuums (pressure differentials) result in greater work load and higher power consumption. Regenerative blowers operate on these principles, and the compressor designation is very relevant in their application. Not only should the fact be considered that higher pressure or vacuum will result in higher power consumption, but also, the fact that these higher pressures or vacuum levels will generate greater heat loads which must be dissipated. With regenerative blowers the heat generated is transferred to the air passing through the blower. A portion of this heat is transferred to the blower housing while the balance remains in the air stream which is discharged from the blower. Therefore, caution must be taken to ensure – 1) that excessive pressure or vacuum is not permitted which may overload the motor – 2) that reduced air flow through the blower due to throttling of the inlet or outlet does not permit the blower to run at excessively high temperatures.  It is obvious that motor overloading will result in high motor temperatures and premature failure.  It is not always as obvious that reduced air flow may cause an over-temperature condition which may result in premature bearing failure.