What Is the Difference Between External Cooling and Internal Cooling in a Gear Pump?

abirami gear pump ecternal gear pump -gear pump diagram

Gear pumps are widely used in industries such as chemicals, oil & gas, hydraulics, plastics, paper mills, and lubrication systems. They are valued for their ability to handle viscous fluids, maintain consistent flow, and operate under pressure. However, one critical aspect of gear pump performance is temperature control. This leads many engineers to ask: What is the difference between an external cooling and internal cooling pump in a gear pump?

Understanding this difference is essential to selecting the right gear pump fo

abirami gear external coling pump

r long-term reliability, efficiency, and safety.

Why Cooling Is Important in Gear Pumps

Gear pumps generate heat due to:

• Friction between gears

• High fluid viscosity

• Continuous operation

• High pressure conditions

If heat is not controlled, it can cause:

• Oil degradation

• Seal damage

• Reduced efficiency

• Premature pump failure

This is why cooling systems are integrated into gear pumps—either externally or internally.

What Is Internal Cooling in a Gear Pump?

Internal cooling uses the pumped fluid itself to absorb and carry away heat generated inside the pump.

How It Works:

• A portion of the process fluid circulates internally

• Heat is transferred from gears and bearings to the fluid

• The fluid carries heat away through normal discharge

Key Features of Internal Cooling:

✔ No external piping required
✔ Compact design
✔ Simple construction
✔ Lower installation cost

Best Suited For:

• Moderate temperature fluids

• Lubricating oils

• Hydraulic systems

• Low to medium viscosity liquids

Limitations:

✘ Not suitable for very high temperatures
✘ Cooling efficiency depends on fluid properties
✘ Less effective for continuous heavy-duty operation

What Is External Cooling in a Gear Pump?

External cooling uses a separate cooling circuit—usually water or oil—to remove heat from the pump body.

How It Works:

• Cooling jackets or external coils surround the pump

• Coolant flows independently from process fluid

• Heat is transferred through pump casing to coolant

Key Features of External Cooling:

✔ Highly effective temperature control
✔ Independent of process fluid
✔ Suitable for extreme conditions
✔ Protects seals and bearings

Best Suited For:

• High-temperature fluids

• Bitumen, polymers, resins

• Continuous heavy-duty operation

• Chemical and petrochemical industries

Limitations:

✘ Higher installation cost
✘ Requires external piping and coolant supply
✘ Slightly more maintenance

Key Differences Between External and Internal Cooling

Which Cooling System Should You Choose?

Choose internal cooling if:
✔ Fluid is lubricating and temperature is moderate
✔ Space is limited
✔ Cost efficiency is a priority

Choose external cooling if:
✔ Fluid temperature is high
✔ Pump runs continuously
✔ Fluid is non-lubricating or sensitive
✔ Long pump life is critical

Impact on Gear Pump Performance and Life

Proper cooling results in:

• Longer seal and bearing life

• Stable viscosity

• Reduced thermal expansion

• Improved volumetric efficiency

• Lower maintenance cost

Incorrect cooling selection often leads to frequent breakdowns and energy loss.

Conclusion

The difference between external cooling and internal cooling in a gear pump lies in how heat is managed and how demanding the application is. Internal cooling offers simplicity and compactness for moderate conditions, while external cooling provides superior temperature control for high-load, high-temperature industrial applications.

Selecting the right cooling method ensures reliable operation, improved efficiency, and extended pump life. Manufacturers like Abirami Pumps design gear pumps with both cooling options to suit a wide range of industrial requirements.