Understanding how elevated temperatures affect pump components is critical to ensuring long service life, reliability and safe operation.
High temperatures fundamentally change how pumps behave — and ignoring that reality is one of the fastest ways to shorten pump life.
Using a standard pump in high-temperature applications can lead to serious issues such as:
⚠ Early Warning Sign
Frequent seal replacement or unexplained efficiency loss is often a symptom of thermal stress, not poor maintenance.
This guide explains how high temperatures impact pump externals, internals, and seals, and what design considerations help mitigate these risks.
Pumps are commonly required to handle heated liquids in processes such as:
| Type of Liquid | Process Description | Examples |
|---|---|---|
| Solids at room temperature | Materials heated to reduce viscosity and improve flow | Molasses, asphalt, palm oil, tallow |
| Process-heated liquids | Liquids heated to initiate, accelerate, or maintain a reaction | Thermal transfer oil, cooking oil, boiler feed, steam condensate |
Operating temperatures in these applications can range from 110°C to over 400°C, depending on the process and fluid properties.
Pump externals include all components exposed to ambient conditions such as the casing, supports, and covers. These parts experience both internal heat transfer and external temperature variation.
Key considerations when selecting external materials include:
Thermal shock occurs when pump components experience rapid temperature changes, for example:
⚠ Common Failure Point
External materials that lack thermal shock resistance can crack or deform when exposed to sudden temperature changes.
Cast Iron
Widely used and cost-effective, but has low thermal shock resistance. Typically suitable up to 345°C.
Low Carbon Cast Steel
Offers higher thermal shock resistance and can handle temperatures up to 425°C, making it more suitable for severe applications.
Internal pump components are less exposed to thermal shock but are highly affected by thermal expansion.
The primary concern with internals is maintaining correct clearances as temperatures rise.
✓ Design Insight
Pumps designed for high-temperature service allow additional internal clearance to compensate for thermal expansion and preserve efficiency.
High temperatures can cause:
For pumps operating continuously at elevated temperatures, internal geometry and material selection are critical to long-term performance.
Seals are one of the most critical and vulnerable components in high-temperature pump applications.
⚠ Common Failure Point
In high-temperature systems, seals are often the first component to fail — not the pump body.
Mechanical seals are commonly used because they:
When handling high-temperature liquids, seal selection depends on:
Seal placement also plays a major role in temperature management.
🛠 Practical Tip
Positioning the seal further down the shaft — away from the hottest internal zones — can reduce seal operating temperature by up to 40°C, significantly extending seal life.
Pumping high-temperature liquids requires careful consideration of materials, clearances, and sealing systems. While the fundamentals apply broadly, no two applications are the same.
If your operation involves hot liquids or thermally demanding processes, working with an experienced pump specialist ensures the correct solution from the outset.
With over 70 years of combined industry experience and manufacturing capability, Allflo Pumps & Equipment supplies engineered pump solutions for infrastructure, construction, mining, water treatment, food processing and industrial applications across Australia.