A Practical Selection Guide

Rotary lobe pumps are widely used in food, beverage, dairy, cosmetic, and chemical industries due to their gentle product handling, stable flow, and hygienic design.

Selecting the right pump involves more than simply choosing a flow rate. Product characteristics, operating conditions, and cleaning requirements all play important roles.

The following five factors should be considered when selecting a rotary lobe pump.

1. Flow Rate

Flow rate is usually the starting point of pump selection.

Common units include:

• L/min
• L/h
• m³/h
• GPM

The required flow rate determines the pump size and operating speed.

Choosing a pump that can achieve the desired flow at a reasonable speed helps reduce wear and product shear.

2. Pressure

System pressure must be carefully evaluated.

Consider:

• Operating pressure
• Maximum pressure
• Pipeline losses
• Filter pressure drop
• Heat exchanger pressure drop

Adequate pressure margins help improve reliability and extend service life.

3. Viscosity

Viscosity is one of the most important factors affecting pump performance.

Typical low-viscosity products:

• Water
• Milk
• Beverages

Typical high-viscosity products:

• Yogurt
• Chocolate
• Syrup
• Honey
• Cream
• Shampoo

Higher viscosity generally requires lower pump speed and higher torque.

4. Temperature

Temperature affects:

• Product viscosity
• Seal life
• Elastomer selection
• Cleaning procedures

Typical applications may range from refrigerated dairy products to hot syrup transfer and CIP cleaning cycles.

5. CIP or COP Cleaning Requirements

Cleaning requirements are critical in hygienic applications.

CIP (Clean-In-Place)

Cleaning without disassembling equipment.

Benefits:

• Reduced downtime
• Improved productivity
• Lower contamination risk

COP (Clean-Out-of-Place)

Cleaning after disassembly.

Benefits:

• Simpler design
• Lower equipment cost
• Suitable for smaller production systems

Users should determine whether CIP capability is required before selecting a pump.

Conclusion

For accurate pump selection, the following information should be provided:

✔ Required flow rate

✔ Operating pressure

✔ Product viscosity

✔ Operating temperature

✔ CIP or COP cleaning requirements

Providing complete process information helps ensure reliable pump performance and long-term operation.