A pressure below atmospheric pressure.

Pressure gauge used to measure pressures below the atmosphere.

Low-pressure air compressors that take suction from a region below atmospheric pressure (turbine condenser) and discharge into the atmosphere.

The number of electrons that an atom tends to gain or lose.

An electron in the outer shell of an atom that takes part in forming chemical bonds or in the flow of electrical current.

Any device modifying or closing off the passage of fluid through a pipe.

That portion of an impeller that throws the water toward the volute case.

A gas particularly one near to equilibrium with the liquid phase of the substance. In general, any gases below its critical temperature.

Any condition that may change continuously such as pressure, temperature, flow rate or level.

A quantity that has both magnitude and direction. The force of gravity is an example of a vector.

The height of fluid equivalent to its velocity pressure.

A word that expresses physical or mental action or a state of being.

The common end point of the two sides of an angle.

A line perpendicular (90 degrees) to the horizontal.

The resistance of a liquid to flow.