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The rated volumetric flow rate for a specific set of parameters.
Capacity (gpm,ft3/hr, m3/hr, )
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The formation and subsequent collapse of vapor in a pump due to suction pressure approaching saturation pressure of the fluid being pumped.
Cavitation
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Operating a pump with the discharge valve closed.
Dead headed
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The maximum distance below the centerline of the pump that the pump is capable of lifting the liquid to the suction eye.
Design suction lift (ft, psi)
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The number of feet the pump moves a liquid up a pipe.
Discharge head (ft, psi, Pa, m)
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A condition in which a pump casing is filled with non-condensable gas or air instead of the fluid being pumped. Can occur as a result of non-condensable gases coming out of solution, or due to incomplete filling and venting of a system.
Gas binding
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The difference between the pressure on the suction side of the pump and the saturation pressure of the fluid being pumped.
Net Positive Suction Head (NPSH) (ft, psi)
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Excessive flow rate in a centrifugal pump that can lead to mechanical stress and abnormally high motor current.
Runout
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The maximum value of head a pump can produce with the pump filled, operating at normal speed and with the discharge valve closed.
Shutoff head (ft, psi)
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The vertical distance in feet from the pump centerline to the free level of the liquid to be pumped (a positive value indicates that no energy is needed to move water to the pump’s centerline).
Static suction head (ft, psi)
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The vertical distance in feet from the pump centerline to the free level of the liquid to be pumped (a negative value indicates the pump must do work to make the fluid to the pump’s centerline).
Static suction lift (ft, psi)
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The vertical distance between the surface of the liquid and the centerline of the pump. It corresponds to the design inlet pressure of the pump.
Suction head (ft, psi)
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A device that moves and/or alters the pressure of fluids in confined spaces with suction or pressure.
Pump
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The vertical distance in feet from the pump centerline to the free level of the liquid plus the velocity head minus all frictional losses in the suction pipe and fittings.
Total suction head (ft, psi)
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The sum of the static suction lift (a negative value) and velocity head minus all frictional losses in the suction pipe and the fittings.
Total suction lift (ft, psi)
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The vertical distance between the free level of the liquid on the suction side and the free level of the liquid on the discharge side.
Total static head (ft, psi)
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The equivalent height in feet that the water would have to fall to reach the speed produced by the action of the pump.
Velocity head (ft, psi)
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List the two major classifications of pumps.
- Positive Displacement
- Kinetic(Dynamic) or Centrifugal
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Describe cavitation, including symptoms.
Cavitation is the formation of vapor bubbles in the eye of a pump and their subsequent collapse on the impeller or in the volute.
Cavitation can be detected by its distinctive sound. The pump sounds like it is pumping rocks. This noise is produced when the vapor bubbles collapse.
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