Effective diameter
In metal bellows terminology it is the calculated diameter where
the pressure penetrates between the metal plates. This number
is used to determine the hydraulic balance diameter of the seal
face.
Efficiency
Power out of the equipment divided by power in.
Elastic range
The stressed part retains its memory and returns to its original
shape.
Elastomer
A rubber like material that, when compressed and then released
will return to 90% of its original shape in less than five seconds.
Electrolysis
A process involving chemical change caused by the passage of
an electric current through a liquid.
Endurance limit.
Beyond this point the metal will fatigue without increasing the
stress.
E.P.A.
Environmental protection agency. A government agency with a mandate
to protect the environment.
E.P.R.
Ethylene propylene rubber. The most common elastomer used in
the sealing of water based and higher pH materials. Cannot be
used in petroleum products.
Extrusion
Permanent displacement of a portion of the O-ring into a gap,
under the action of fluid pressure.
Eye of the impeller
The center of the impeller, where the fluid enters.