When selecting a mixer, it is important to consider the parts involved in the mixing and dispersing process. The impeller blades you use with your mixers will ultimately determine the accuracy of your mixture. An impeller blade is usually made of stainless steel, carbon steel, aluminum, brass, bronze or plastic, and is designed to accelerate the liquid in a specific direction. Different impeller blades are used for specific mixture types. There are four main impeller blade types that you can choose from; airfoil, pitch blade, propeller blade, or radial blade.
An airfoil or dynaflow impeller blade is designed to produce maximum airflow with the lowest shear. A lower shear means that it would not be well-suited for thicker mixtures. An airfoil impeller blade would be suitable for mixtures with a low to medium viscosity. Its combination of high flow, high mixing intensity and low shear makes it the best for liquids that are shear-sensitive. Shear-sensitive liquids can either be temporarily or permanently damaged if you do not use the correct shear to mix the liquid.
The pitch blade impeller is the most versatile option out of any impeller you can choose from. It was the standard blade until the airfoil was created. The pitch blade impeller is ideal for applications that require a combination of pumping and shearing. It has a high mixing intensity, with medium flow for mixtures that are of medium viscosity.
The propeller blade or marine-type impeller blades work well with low to medium viscosity mixtures. They are modeled after the propellers on marine boats. They are used mostly in smaller, portable direct drive mixers because they are efficient and economical. The marine-type impeller blades have a medium shear with medium to high mixing intensity.
Curved Radial impeller blades are also available. The application for these blades would be for mixtures that require agitation close to the bottom of the tank, or applications where shear is the main requirement. The angle of attack on these blades gives higher shear rates, although the mixing intensity and flow is much lower than the other blade types.
There are many newer blade types in addition to these core impeller blades. It is important to know what impeller blades you will need for your mixer to attain the desired results you are looking for. If you need help selecting impeller blades for your mixer, contact NorstoneInc.com today and our specialists will be happy to help you!