Knowledge sharing on “All about Centrifugal Pumps” for Engineering students/young Engineers/professionals of oil & gas industry. Series -5

 When are self -aligning ball bearings and self aligning roller bearings used in centrifugal pumps?

For heavy loads, high speeds, and long bearing spans with no end thrust, self-aligning ball bearings  can well be adopted for line bearings on centrifugal pumps. The double row of balls runs in fixed grooves in the inner or shaft race, and the outer race is spherically ground (Fig-1); Therefore it operates as a pivot to take slight vibration or shaft deflection. It has very little thrust load (axial load) capacity and hence is not used for combined radial and thrust load in centrifugal pumps. With large shafts, the self- aligning spherical roller design is used instead of self- aligning ball bearings.

Self-aligning spherical roller bearings (Fig-2) can carry a combined radial and axial load with considerable thrust load component.

Fig-1.Self-aligning ball bearings

Fig-2.Self-aligning spherical roller brg.