When selecting and designing pump bearings, the harsh working environment must be taken into account:
The threat of water: The infiltration of moisture and water vapor is the primary cause of bearing failure. It can lead to the emulsification and deterioration of lubricating grease, as well as the rusting of the bearings.
Complex loads:
Radial load: Caused by the imbalance of the impeller, the gravitational force of the rotor, and the pulling force of the pipeline.
Axial load: Generated by the pump's head (pressure difference), especially in single-suction pumps, the axial force is very significant.
Speed and temperature rise: The water pump usually operates continuously. The bearings generate heat, and lubricating grease is required to enable stable operation within a certain temperature range.
Vibration and alignment error: Installation misalignment, large diameter of the shaft, and other factors can cause vibration. Therefore, the bearing needs to have a certain ability to self-align.
Summary
The pump bearing is a highly engineered component. Its selection is a crucial aspect in the design of the pump, requiring a comprehensive balance of load, speed, environment, lifespan and cost. For the majority of general-purpose clear water pumps, the most common and economical choice is the deep groove ball bearing lubricated with lithium-based composite grease, with C3 clearance and double-sided rubber seals (2RS). However, for more demanding conditions, more specialized bearing types and configurations need to be selected.
