There are at least 5 common types of bearing, each of which operates on different principles: Bearings constrain relative motion of the shaft (rotor) and reduce friction between the rotating shaft and the stator. Centrifugal pumps are provided with packing rings or mechanical seal which helps prevent the leakage of the pumped liquid. Shaft is a mechanical component for transmitting torque from the motor to the impeller. The diffuser directs the flow, allows a more gradual expansion and therefore increases the efficiency of the centrifugal pump. A diffuser is a set of stationary vanes that surround the impeller. Some centrifugal pumps contain diffusers. Therefore, according to Bernoulli’s principle, the volute converts kinetic energy into pressure by reducing speed while increasing pressure. The volute of a centrifugal pump is the casing that receives the fluid being pumped by the impeller, slowing down the fluid’s rate of flow. The volute is a curved funnel that increases in area as it approaches the discharge port. The casing contains the liquid and acts as a pressure containment vessel that directs the flow of liquid in and out of the centrifugal pump. Impeller is a rotor used to increase the kinetic energy of the flow. These components are designed to perform specific tasks: The mechanical end of the pump includes the pump shaft, sealing, bearings and shaft sleeve. The mechanical end includes those parts that support the impeller within the casing. In this case also bearing can belongs to wet ends. In some cases the first radial bearing can be water lubricated. The two primary wet ends are the impeller and casing. The wet end of the pump includes those parts that determine the hydraulic performance of pump. These components can be subdivided into the wet end and the mechanical end. There are a few components that virtually every centrifugal pump has in common. Each centrifugal pump is made of hundreds of parts.