How to Select the Right Bearings for Centrifugal Pumps: Rolling vs. Sliding Bearings
Share
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:
Speed & Size Limit:
n × Dcp < 500,000
Where:
- n = Rotational speed (rpm)
- Dcp = Average bearing diameter (mm) = (D + d)/2
Power Limit:
n × Pa < 4,000,000
Where Pa = Rated power (kW)
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 = √(p × u³)
Where:
- p = Average unit pressure (MPa) = F/(d × l)
- u = Peripheral speed (m/s) = π × d × n / 60
| 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
- ✓ Monitor vibration & temperature (predictive maintenance)
- ✓ Use proper lubrication (avoid over/under-greasing)
- ✓ Align shafts correctly (misalignment causes premature wear)
- ✓ Choose the right seal (prevents contamination)
Where to Find High-Quality Bearings for Centrifugal Pumps?
Looking for reliable rolling bearings or heavy-duty sliding bearings? CXE Bearing offers:
- API 610-compliant bearings
- Custom solutions for extreme conditions
- Technical support & lifetime guidance