This is similar to other impeller pumps,
but the fluid being pumped is not sent in a circular path. Rather, it proceeds
more or less in a straight direction up to the discharge elbow. Shown is a
vertical propeller pump (horizontal and angled versions also exist). Here, the
motor sits above the discharge shaft. The distance to the propeller is usually
well under 100 feet and often between 10 and 20 feet.
The propeller can be
placed below the surface of the liquid, where it will always be primed.
Propeller
pumps are generally high-speed but with low heads. They can be quite large, measuring
over a dozen feet in diameter and moving over 50,000 gallons per minute. Some
have adjustable-pitch blades.
(This is a still representation and possibly also a low-resolution
image of a pump which is fully animated in the CD-ROM version of this glossary.)
