The Impact of Viscosity on Industrial Pump Efficiency
By PumpWorks / January 22, 2025
What is viscosity and how does it affect the performance and efficiency of industrial pumps? Keep reading to find out.
What is Viscosity?
Viscosity is the measurement of a fluid’s resistance to flow. It describes how thick or thin a fluid is and is commonly compared to the thickness of oil. A higher viscosity means a thicker fluid, while a lower viscosity indicates a thinner fluid. The unit of measurement is typically centipoise (cP) or pascal-seconds (Pa·s).
How Viscosity Affects Pump Performance
The viscosity of the fluid directly impacts the power required for pumping, the type of pump best suited for the job, and the efficiency of the system.
Power Consumption
Fluids with higher viscosity require more power to move through the pump. This is because thicker fluids have more resistance to flow, forcing the pump to work harder. The higher the viscosity, the greater the energy consumption.
Example:
- Water has a viscosity of 1 cP and requires less power to pump.
- Honey has a viscosity of around 10,000 cP, requiring much more power to move.
Pump Selection
Not all pumps handle high-viscosity fluids equally well. Some pumps are better suited for thicker fluids due to their design and operating principles. For instance:
- Centrifugal Pumps: While ideal for low-viscosity fluids, they lose efficiency with higher-viscosity fluids due to increased friction and flow resistance.
- Positive Displacement Pumps: These pumps perform better with high-viscosity fluids. They move fixed amounts of fluid per cycle, regardless of viscosity.
Flow Rate & Efficiency
Viscosity impacts the flow rate of a pump. Higher viscosity fluids result in lower flow rates, which can reduce overall system efficiency. To maintain consistent flow rates, adjustments must be made to the pump’s speed, size, or design.
Key Factors Influencing Viscosity’s Impact
Several factors affect how viscosity influences pump efficiency. Understanding these factors is essential for optimizing pump performance.
Temperature
Viscosity changes with temperature. As the temperature increases, the viscosity of many fluids decreases, allowing for easier flow. Pumps running at higher temperatures often experience reduced power consumption and improved efficiency.
Tip: If you’re handling high-viscosity fluids, consider using heating elements to reduce viscosity and improve flow.
Pump Speed
Higher pump speeds can improve the flow of higher-viscosity fluids. However, increasing speed may also lead to higher wear and tear on the pump components and increased maintenance costs.
Tip: Find the optimal pump speed for your specific fluid and system to balance performance and longevity.
Fluid Composition
The chemical makeup of a fluid can also impact its viscosity. Fluids with suspended solids or particulate matter can have varying viscosity levels, which may require pumps with more durability and specialized features.
Tip: If dealing with fluids containing solids, select a pump with a high tolerance for abrasives or a self-priming pump.
Types of Pumps for Different Viscosities
Choosing the right pump for a specific fluid viscosity is critical to maximizing efficiency and minimizing downtime. Below is a guide to help you select the best pump for various viscosity ranges.
Viscosity Range | Recommended Pump Type |
Low (1–100 cP) | Centrifugal Pump |
Medium (100–1,000 cP) | Gear Pump, Screw Pump |
High (1,000–50,000 cP) | Progressive Cavity Pump, Peristaltic Pump |
Very High (>50,000 cP) | Positive Displacement Pump |
Low Viscosity Fluids
For fluids like water or light oils, centrifugal pumps work well. Their efficiency is highest when dealing with low-viscosity fluids, offering high flow rates and low power consumption.
Medium to High Viscosity Fluids
For fluids like syrups, oils, and lubricants, gear pumps or screw pumps are ideal. They are more efficient than centrifugal pumps for moderate to high-viscosity fluids.
Very High Viscosity Fluids
For thick materials like pastes, adhesives, or slurries, positive displacement pumps, including progressive cavity and peristaltic pumps, are best. These pumps maintain consistent flow rates regardless of viscosity changes.
Impact of Viscosity on Pump Maintenance
High-viscosity fluids can cause excessive wear on pump components. More force is needed to move the fluid, which can lead to issues such as:
- Increased strain on seals and bearings
- Higher likelihood of cavitation
- Greater heat generation in the system
Tip: Regular maintenance is essential for high-viscosity systems. Inspect seals, bearings, and fluid temperatures to avoid breakdowns.
Seal and Bearing Wear
Higher-viscosity fluids place extra strain on seals and bearings, accelerating wear. It’s essential to use materials resistant to the type of fluid being pumped and check these components frequently.
Cavitation Risks
In high-viscosity fluids, cavitation may occur due to increased pressure differentials. Cavitation can cause significant damage to pump components and reduce efficiency. Proper pump selection and maintenance can mitigate these risks.
How to Improve Pump Efficiency for High-Viscosity Fluids
To maximize pump efficiency when dealing with high-viscosity fluids, here are some key considerations:
- Use a pump with the right design. Choose a pump designed for higher viscosities, such as a positive displacement pump, to maintain consistent flow.
- Optimize pump speed. Adjust pump speed to match the viscosity of the fluid. Slower speeds may improve efficiency in some cases, but it’s important to strike a balance.
- Maintain proper fluid temperature. Keeping the fluid at a temperature that reduces viscosity can improve efficiency. This is especially useful in systems handling thick oils, waxes, or resins.
- Monitor pressure drops. High-viscosity fluids increase friction in the system, leading to pressure drops. Monitoring and managing these drops can improve pump efficiency.
Contact PumpWorks Today
At PumpWorks, we specialize in providing high-quality industrial pumps designed to handle a wide range of viscosities. Reach out today to learn more about our reliable and efficient pumping solutions.