Centrifugal pumps consist of a set of rotating vanes, enclosed within a housing or casing, used to impart energy to a fluid through centrifugal force. The pump has two main parts: a rotating element which includes an impeller and a shaft, and a stationary element made up of a casing (volute or solid), stuffing box, and bearings. Centrifugal pumps operate using kinetic energy to move fluid utilizing an impeller and a circular pump casing. The impeller produces liquid velocity and the casing forces the liquid to discharge from the pump converting velocity to pressure. This is accomplished by offsetting the impeller in the casing, and by maintaining a close clearance between the impeller and the casing at the cutwater. The fluid enters the pump near the center of the impeller and is moved to its outside diameter by the rotating motion of the impeller. The vanes on the impeller progressively widen from the center of the impeller that reduces speed and increases pressure. This allows centrifugal pumps to produce continuous flows at high pressure. By forcing the fluid through without cupping it, centrifugal pumps can achieve a very high flow rate.
Centrifugal pumps are used in many industries. Some of their most common applications /media transferred include: general purpose fluids, pure water, sludge and sewage, slurry, high viscosity fluids, power generation, the paper industry, the petroleum industry, chemicals and corrosives, gravel and solid materials, high temperature materials, and marine applications.
Centrifugal pumps generate flow by using one of three actions: radial flow, mixed flow, and axial flow. These classifications do not rate the performance quality of the pump, they are merely groupings based upon the pump’s action.
Radial flow pumps are centrifugal pumps in which the pressure is developed wholly by centrifugal force. In mixed flow pumps, the pressure is developed partly by centrifugal force and partly by the lift of the vanes of the impeller on the liquid. Axial flow centrifugal pumps develop pressure by the propelling or lifting action of the vanes of the impeller on the liquid.
