Challenges in Pumping Highly Viscous Fluids
Pumping highly viscous fluids is a nuanced task, demanding specific approaches and equipment due to the inherent resistance to flow that these liquids exhibit. Viscosity, a measure of a liquid's resistance to flow, varies across different substances and can be influenced by temperature. Highly viscous fluids, akin to honey or cold maple syrup, flow much slower compared to less viscous counterparts like water. When heated, these fluids become less dense, allowing molecules to move more freely.
Considerations and Challenges
-
Viscosity Variation with Temperature: Viscosity changes with temperature, affecting the fluid's flow properties. Effective pumping solutions must accommodate variations, ensuring consistent performance across different temperature ranges.
-
Resistance to Flow: Highly viscous fluids resist flow, making it challenging to pump them efficiently. As viscosity increases, traditional centrifugal pumps become less effective, necessitating alternative technologies for successful pumping.
-
Preventing Separation and Suspension Issues: Certain viscous fluids contain solids or particles. Careful handling is vital to prevent separation, ensuring uniform consistency and suspension of solids within the liquid.
Best Practices and Pump Selection:
Highly viscous fluids demand specific pump types and operational strategies:
| AODD | 20,000 cP |
| Centrifugal | 200 cP |
| Circumferential Piston | 1,000,000 cP |
| Eccentric Disc | 3,000 cP |
| Gear | 1,000,000 cP |
| Metering | 5,000 cP |
| Peristaltic Hose | 25,000 cP |
| Peristaltic Tube | 10,000 cP |
| Rotary Lobe | 700 cP |
| Rotary Vane | 22,000 c |
As the density and thickness of a fluid increases, it becomes increasingly difficult to flow and pump with a centrifugal pump. Typically the thicker the fluid a different technology is required being positive displacement pumps, as with a centrifugal pump the thicker the fluid is the more it recirculates within the pump head.
Examples of Highly Viscous Fluids
- Molasses: A thick, syrupy liquid extracted from sugar cane or sugar beet.
- Molten Chocolate: Chocolate in its liquid state is highly viscous, requiring careful handling during industrial processes.
- Polymer Melts: Molten polymers used in manufacturing processes often have high viscosity.
- Adhesives and Sealants: Viscous adhesives and sealants used in construction and manufacturing applications.
- Lubricating Grease: Thick, viscous lubricants used in automotive and industrial machinery.
Pumps which handle high viscosity typically have larger inlets, run slower, and are consequently more efficient with such fluids than a centrifugal pump. Some high viscosity liquids require careful handling to prevent changes to its consistency, ensure parts of the liquid do not separate out and that solids remain in suspension.
Successful handling of highly viscous fluids involves understanding viscosity changes, selecting appropriate pump types, and implementing precise operational techniques. With a wide array of pump technologies and expertise, AxFlow ensures efficient and reliable solutions for pumping challenges posed by viscous substances, ensuring consistency and quality across various industrial applications.
