How to Select the Right Bearings for Centrifugal Pumps: Rolling vs. Sliding Bearings

Introduction

Choosing the correct bearings for centrifugal pumps is critical for performance, longevity, and reliability. The two main types—rolling bearings (ball/roller bearings) and sliding bearings (plain/bush bearings)—have distinct advantages depending on operating conditions.

This guide explains:

• When to use rolling bearings vs. sliding bearings (API 610 standards)
• Lubrication methods for sliding bearings
• Key factors in bearing selection

1. Rolling Bearings vs. Sliding Bearings: Selection Criteria

When to Use Rolling Bearings (API 610 Standard)

According to API 610, rolling bearings should be used if:

Minimum Service Life Requirements:

• ✓ 25,000 hours (rated conditions)
• ✓ 16,000 hours (non-rated conditions)

📌 If values exceed these limits → Use sliding bearings.

Advantages of Rolling Bearings in Centrifugal Pumps

• ✓ Lower friction → Higher efficiency
• ✓ Easier maintenance
• ✓ Better for moderate speeds & loads

2. Lubrication Methods for Sliding Bearings

The lubrication method depends on the average load number (K):

K Value	Lubrication Method	Cooling Required?
K < 2	Grease lubrication	No
2 < K ≤ 15	Oil lubrication (no cooling)	No
15 < K ≤ 30	Oil ring/splash lubrication	Yes (water/circulating oil)
K > 30	Forced lubrication (pressure-fed)	Yes

3. Key Factors in Bearing Selection for Centrifugal Pumps

1. Load & Speed

• High speed & moderate load → Rolling bearings
• Very high load or extreme speed → Sliding bearings

2. Operating Environment

• Corrosive/contaminated fluids? → Stainless steel or ceramic rolling bearings
• High temperatures? → Special alloy sliding bearings

3. Maintenance Requirements

• Rolling bearings → Easier to replace
• Sliding bearings → Require precise lubrication management

4. Cost Considerations

• Rolling bearings → Lower initial cost
• Sliding bearings → Higher durability in extreme conditions

4. Best Practices for Extending Bearing Life