Graphalloy vs. PEEK: Solving Premature Bearing Wear in Food-Grade Gear Pumps

A French precision-machining workshop was tasked with redesigning a horizontal gear pump used for dosing food-grade additives. Despite careful engineering, PEEK bushings in the pinion bearings wore out prematurely, jeopardizing product quality and production schedules.

• Medium: Non-abrasive but highly viscous additive—fluid when hot, toothpaste-like when cold
• Temperature: Up to 150 °C (302 °F)
• Speed: 80–120 RPM under continuous high pressure
• Environment: CIP-compatible, food-contact zone

PEEK’s standard lubrication grooves became a liability: during shutdown, product seeped into the grooves, solidified, and welded itself to the stainless-steel shaft. Each restart produced micro-scoring and accelerated wear—an expensive cycle of replacements and downtime.

The engineering team sought a self-lubricating solution that could:

1. Operate dry or flooded without supplemental grease or oil
2. Withstand 150 °C without softening or swelling
3. Meet FDA guidelines for incidental food contact
4. Eliminate grooves yet maintain hydrodynamic stability

Our FDA-acceptable bronze GRAPHALLOY^® grade checked every box. Because Graphalloy’s graphite matrix provides continuous lubrication, the bushings could be supplied without grooves, removing the pocketing issue entirely.

Within two weeks, prototype bushings were machined, installed, and run under full load. The trials were so conclusive that the customer wanted an urgent repeat order: four replacement bushings for the original pump plus six larger units for an upsized model. Standardization across the plant is now underway.

• Self-lubrication
• Dimensional stability — minimal thermal expansion compared to polymers
• Chemical resistance — inert to most food additives and cleaning agents
• FDA acceptable grades available

Switching to self-lubricating Graphalloy bushings eliminates product entrapment, cuts maintenance, and boosts uptime.

If your process suffers from similar wear modes, consider evaluating Graphalloy. Our application engineers can size, machine, and ship prototypes quickly.

Learn more at graphalloy.com/html/features.html.