Ball bearings vs sleeve bearins

BALL BEARINGS VS. SLEEVE OR JOURNAL BEARINGS B013

• The ball bearing is described in the left illustration.
• The illustration on the right shows a sleeve or journal bearing

When do you make the change from anti-friction ball and roller bearings to hydrodynamic (sleeve) bearings in a centrifugal pump?

• Any time the DN number exceeds 300,000. To get the DN number all you have to do is multiply the bearing bore by the shaft rpm.
• If the standard bearings fail to meet an L₁₀ life of 25,000 hours in continuous operation or 16,000 hours at maximum axial and radial load and rated speed.
• If the product of the pump horsepower and speed in rpm is 2.7 million or greater.