Design Considerations for Low to High Viscosity Industrial Mixers
In th
is IN THE MIX blog, we explore design considerations for industrial mixers based on the viscosity of fluids being mixed. Considerations include motor horsepower, running speed, fluid temperature and impeller design.
Before looking at the recommended impeller types for low to high viscosity fluids, let’s quickly define viscosity and how it’s measured.
What is the Definition of Viscosity?
Viscosity is a fundamental property of fluids that quantifies their resistance to deformation or flow under applied stress. It is a critical factor in numerous industrial processes, affecting how fluids are handled, mixed, and processed. The design of industrial mixers is heavily influenced by the viscosity of the materials being mixed, as it determines the mixer type, speed, power, and efficiency required to achieve optimal mixing.
How is Viscosity Measured?
Viscosity is measured in units called Pascal-seconds (Pa·s) or, more commonly, centipoise (cP). It can vary significantly among different fluids, ranging from low-viscosity liquids like water to high-viscosity substances like honey or tar. Viscosity is affected by temperature, with most fluids becoming less viscous as they are heated. Having an accurate viscosity value of the material you want to mix is extremely important. This has a direct effect on the industrial mixer specifications.
How Does Viscosity Impact the Type and Size of Mixing Impellers?
The shape, size, and placement of impellers influence the mixing efficiency. Impellers must be designed to match the viscosity and rheology of the materials, ensuring optimal flow and shear conditions.
Here are the recommended ProQuip mixing impellers based on the viscosity of the fluids being mixed.
Mixing Impellers for Low Viscosity Applications
Low viscosity mixing impellers are designed to create high flow and lower shear which is ideal for mixing low-viscosity fluids.
A good example is the ProQuip HiFlow™ High Efficiency, Low Viscosity Hydrofoil Impeller. It produces a very high flow/shear ratio for maximum pumping action and efficiency in low viscosity, flow controlled mixing processes.
ProQuip HiFlow High Efficiency Low Viscosity Hydrofoil Impeller
Mixing Impellers for Low and High Viscosity Applications
Axial turbine impellers like the ProQuip Axial Flow Turbine Impeller (45° Pitched Blade) are designed to handle a wide range of viscosities. These impellers are characterized by their axial flow pattern, which directs fluid parallel to the impeller shaft. This design allows for efficient mixing in both low and high viscosity applications by generating a strong flow with moderate shear.
The ProQuip Axial Flow Turbine Impeller (45° Pitched Blade)
Mixing Impellers for High Viscosity Applications
High viscosity mixing impellers are designed to handle the additional resistance posed by thicker fluids. These impellers are engineered to provide high shear and low flow, which is essential for breaking down and thoroughly mixing high-viscosity materials. Examples of high viscosity mixing impellers include anchor, gate, and helical ribbon impellers.
High viscosity mixing impellers are designed to handle the additional resistance posed by thicker fluids. Examples include anchor, gate and helical ribbon impellers. These designs ensure that even the most viscous materials are adequately mixed, achieving a homogeneous mixture with consistent properties throughout the batch.
Examples of high viscosity impellers include the ProQuip anchor, double helix and gate impellers.
ProQuip Anchor Impeller
ProQuip Double Helix Impeller
ProQuip Gate Impeller
Two other examples of high viscosity impellers include the ProQuip HiFlow™ Doubly-Pitched, Variable Viscosity Hydrofoil Impeller (efficient, low power mixing without the use of baffles) and Doubly-Pitched Axial Flow Turbine Impeller (pumps in both directions in baffled and non-baffed applications).
ProQuip HiFlow Doubly-Pitched-Variable Viscosity Hydrofoil Impeller
ProQuip Doubly-Pitched Axial Flow Turbine Impeller
Conclusion
Understanding the properties of the materials being mixed and selecting the appropriate mixer design are crucial for achieving efficient and effective mixing. Whether in food production, pharmaceuticals, chemicals, cosmetics, or construction, industrial mixers are indispensable tools that drive innovation and quality in manufacturing processes.
For More Information
If you are struggling to solve a difficult mixing application, contact us today at applications@proquipinc.com or 330-468-1850 to discuss the comprehensive lab services we offer including viscosity testing. These services are provided by ProQuip applications engineers with expertise in determining the right agitator solution to meet your mixing needs.
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Related Articles
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Viscosity Affect on Industrial Mixers
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ProQuip Tank Agitators – Designing and Manufacturing Top-Quality, Cost-Effective Industrial Mixing Solutions Since 1969.
