Introduction
At a German incinerator supplied by Stamag in Landsberg, a unique challenge existed: bearings needed to operate fully submerged in boiling hot water, surrounded by floating hot embers and ash.
The Challenge
The bearing requirements were severe: complete submersion, water temperature reaching 100°C, hot ash particles, constant corrosion, and continuous operation. Stamag had tried numerous solutions, but all failed. Water penetration, seal destruction from heat, or ash contamination inevitably led to failure.
The Solution
Martin Metterhausen of Wälz- und Gelenklager Lüneburg worked with Jaap Meeuwsen to develop the EXT 80 CL C3 20: a take-up bearing with CL seals featuring PTFE lips creating a 0.02mm gap too small for ash but accommodating thermal expansion, C3 internal clearance for 100°C operation, and silicone grease for extreme temperatures.
Results
Years of continuous operation without failure. The shaft rotates at only 1.5-2 RPM creating enormous torque while completely submerged in boiling water. Zero water penetration, complete heat resistance, and ash particle protection achieved. "This demonstrates what 'extreme' really means," says Martin.
Key Takeaways
- Customization is essential for truly extreme applications
- PTFE seal lips withstand 100°C+ where rubber fails immediately
- Microscopic 0.02mm seal gaps provide protection and thermal accommodation
- Complete system engineering solves "impossible" applications