Radial Bearings for Pumps

Radial bearings support the pump shaft perpendicular to the axis of rotation, ensuring shaft stability, alignment, and smooth operation under hydraulic and mechanical loads.

Main Functions

• Support radial forces from the impeller(s).
• Keep shaft alignment precise for seals and hydraulic parts.
• Minimize friction, wear, and vibration.
• Increase pump efficiency and reliability.

Types of Radial Bearings in Pumps

1. Carbon / graphite bearings
   • Self-lubricating, corrosion-resistant.
   • Water- or product-lubricated.
     → Used in submersible, multistage, condensate, boiler feed pumps.
2. Ceramic radial bearings
   • Silicon carbide (SiC):
     • Extremely hard and wear-resistant.
     • Excellent thermal conductivity.
     • Outstanding chemical and corrosion resistance (acids, seawater, slurries).
     • Common in chemical process pumps, seawater pumps, slurry pumps.
   • Aluminum oxide (Al₂O₃):
     • High hardness and good chemical resistance.
     • Good dimensional stability at high temperatures.
     • Often used in clean-water and chemical pumps where cost is a factor.
3. Composite / polymer bearings
   • PTFE, PEEK, reinforced composites
   • Good dry-running capacity, low friction.
     → Applied in chemical and seawater service.
4. Sleeve / journal bearings
   • Bronze, brass, or babbitt alloys.
   • Oil- or grease-lubricated.
     → Found in large or slow-speed pumps.
5. Rolling-element bearings
   • Ball bearings (deep groove, angular contact)
   • Roller bearings (cylindrical, needle)
     → Common in end-suction and process pumps.

Usually are placed:

• Near motor/coupling side
• Near impeller/seal side
• Intermediate radial guide bearings in long-shaft and multistage pumps for shaft stability.

Applications

• Submersible pumps → carbon or SiC radial bearings, water-lubricated.
• Multistage high-pressure pumps → carbon or ceramic guide bearings + thrust bearing.
• Chemical process pumps → SiC or Al₂O₃ for corrosion and wear resistance.
• Seawater pumps → SiC or polymer bearings for saltwater.
• Slurry pumps → SiC bearings, highly abrasion resistant.
• Boiler feed/condensate pumps → carbon or ceramic radial guide bearings.