Progressive (or Progressing) Cavity pumps,
a type of Single Screw pump, are used for highly viscous liquids such as peanut
butter or glue, and also for liquids with significant amounts of solids such as
cement or sand slurry. Fuild proceeds from the entrance, at the top on the
right side here, to the left. The rotor revolves inside the stator.
The stator
is a twisted cavity with an oval-shaped cross-section. It is usually made of natural
or synthetic rubber, steel, or plastic. The rotor is usually steel.
For a
given diameter and shape of the rotor, doubling the number of stages (the length)
will double the output pressure.
The area of the cross-section of the rotor
determines the backpressure the pump must withstand.
(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.)
