Centrifugal Pumps

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:

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 loadRolling bearings
  • Very high load or extreme speedSliding 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
Contact us today for expert bearing selection!
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