U.S. Department of Energy - Energy Efficiency and Renewable Energy
Federal Energy Management Program – Operations and Maintenance
Key Components of Pumps
Centrifugal Pumps
| Component |
Description |
| Impeller and volute |
The two main components of a centrifugal pump are the impeller and the volute.
The impeller produces liquid velocity and the volute forces the liquid to discharge from the pump converting velocity to pressure. This is accomplished by offsetting the impeller in the volute and by maintaining a close clearance between the impeller and the volute at the cut-water. A centrifugal pump impeller slings the liquid out of the volute. |
Positive Displacement Pumps
Single Rotator
| Component |
Description |
| Vane |
The vane(s) may be blades, buckets, rollers, or slippers that cooperate with a dam to draw fluid into and out of the pump chamber. |
| Piston |
Fluid is drawn in and out of the pump chamber by a piston(s) reciprocating within a cylinder(s) and operating port valves. |
| Flexible Member |
Pumping and sealing depends on the elasticity of a flexible member(s) that may be a tube, vane, or a liner. |
| Single Screw |
Fluid is carried between rotor screw threads as they mesh with internal threads on the stator. |
Multiple Rotator
| Component |
Description |
| Gear |
Fluid is carried between gear teeth and is expelled by the meshing of the gears that cooperate to provide continuous sealing between the pump inlet and outlet. |
| Lobe |
Fluid is carried between rotor lobes that cooperate to provide continuous sealing between the pump inlet and outlet. |
| Circumferential piston |
Fluid is carried in spaces between piston surfaces not requiring contacts between rotor surfaces. |
| Multiple Screw |
Fluid is carried between rotor screw threads as they mesh. |
Relief Valves
NOTE: It is essential to have a relief valve on the discharge side of a positive displacement pump.
| Component |
Description |
| Internal relief valve |
Pump manufacturers normally have an option to supply an internal relief valve. These relief valves will temporarily relieve the pressure on the discharge side of a pump operating against a closed valve. They are normally not full ported, i.e., cannot bypass all the flow produced by the pump. These internal relief valves should be used for pump protection against a temporary closing of a valve. |
| External relief valve |
An external relief valve installed in the discharge line with a return line back to the supply tank is highly recommended to provide complete protection against an unexpected over pressure situation. |
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