1. Solving Bearing Misalignment Issues for STP Feed Pumps
STP - James Alston, System Engineer
Sulzer Pump - Art Washburn, PE
Pioneer - Lyle Branagan, PE
EPRI FSRUG - San Antonio, TX
February 2011
Copyright 2009 Pioneer Motor Bearing Company

2. Sulzer 22 x 22 x 17 CD 1 Stage Horizontal Pump

3. Out-board Bearing

4. In-board Bearing

5. Pump Side View (Thrust End)

6. STP FW Pump Design Vintage, 1978 Service, Steam Generator Feed Water
15, FT
5420 RPM
SG 0.88 (Temperature, 373 deg F)
Horsepower, 10,000 BHP (max)
Bearing L/D Ratio, 0.72

7. Performance Curve (Multistage)

8. Performance Curve (Certified)

9. Performance Curve (NPSHR Knee)

10. Misalignment Damage on Pump Sleeve Bearing
Upper half
Damage found on the pump bearing due to misalignment with the turbine.
Lower half
Turbine side
Turbine side
Investigated
October 2005

11. Observed babbitt fatigue damage
Damage due to cyclic stresses from vibration.
Can also be due to misalignment or looseness forces.

12. Alternative Pump Bearings
Want to handle wide range of misalignment
Accompanied by wide range of bearing loads
Tilting pad design handles load range
Select pivot for best misalignment accommodation
Design misalignment 0.058”