Impellers Vs. Propellers

Canamix industrial agitators provide high quality mixing solutions for a broad range of industries. These industries span from mining to pharmaceutical to paper and more. Each industry’s mixing applications have unique requirements that can only be met when the right equipment is used. With our technical expertise, Canamix can provide agitators specifically designed to deliver the desired results.

One key element in designing mixing solutions is selecting the correct agitator impeller. But what exactly is an impeller, and what are the differences between an impeller and a propeller?

Propellers

Propellers propel (extrinsic)

A propeller is a type of fan that produces linear thrust. As the propeller turns, a pressure difference is created on the front and back of the blades. This pressure sends a fluid (usually air or water) out behind the propeller. The blades have a unique aerofoil shape which helps produce more pressure and therefore more thrust. Under theoretically ideal conditions, the air or water around a plane or boat propeller would stay static while the vehicle moves. In an agitation scenario, the impeller is static while the fluid moves.

Generally, propellers propel, which is an extrinsic action.

Impellers

Impellers impel (intrinsic)

While propellers produce linear thrust, an impeller can produce both axial and radial thrust, depending on the setup. This means that the fluid can be sent outward from the centre of the rotation as well as in a linear direction.

Impellers are made with the same principles, however, maximum efficiency can only be achieved with the right combination of the agitation method selected by the manufacturer, the impeller design, and the accuracy of the blade profiles.

We can further break down the categorization of impellers into three different types.

High, Medium, And Low Solidity Impellers

Impellers can be categorized as “high,” “medium,” and “low” solidity types. High solidity impellers have large square-shaped blades that are primarily used for gas dispersion, as well as medium to high viscosity blending. The size and design of the blades prevent gas from just flowing around them, which would happen if narrow blades were used. Low solidity impellers are much thinner. For solid suspension and low viscosity blending, these are the impellers of choice.

Below you can see the differences between a low, medium, and high solidity impeller.

High Solidity Impeller

Medium Solidity Impeller

Low Solidity Impeller

Conclusion

While early propellers and impellers were fundamentally different, modern propellers and impellers both use aerofoil theory for design, which is based on Bernoulli’s principle.

We’ve established that while propellers can propel and produce linear thrust, an impeller can produce both axial and radial thrust.

Impellers are often contained within a pump housing and use vanes to draw in fluid, while propellers use blades to push liquid away. In centrifugal pumps, impellers are often used to create pressure to move slurries through pump housing.

Even with a clear understanding of the differences between impellers and propellers, your operation should not be limited to just these two concepts. There are many scenarios, for example, where a centrifugal pump is overshadowed by a peristaltic pump.

Regardless of whether your operation relies on a centrifugal or peristaltic pump, you should always consider the long-term value of your operational setup. Which pump wins out in terms of long-term performance? Which one will detract from your bottom line with additional maintenance costs? When it comes to optimizing your operation, you should consider contacting a mixing expert for guidance.

Sepro Mixing has a modern solution for any industrial agitation project. With access to dozens of agitator impeller types, drives, and tank geometries, we provide the best mixing solutions for our customers. Whether an application needs flow, gas dispersion, chemical reactions, solid suspension, or any combination of these, there is a Sepro agitator that can handle it. Speak to an industrial agitator expert today to get started!