Glossary O
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The following definitions are intended to give basic understanding of the terms
commonly used in the pump industry. Some industry standards, or customer
specifications, may have specific meaning of certain terms that may be different
from their common usage - in such case the terms should be interpreted in the
context of the standards, or specifications, being referred to.
Oiler -

Oil mist lubrication - a lubrication system in which oil mist is produce by
compressed air to lubricate the bearing, or bearings. It is usually used in high
speed application. See pure oil mist lubrication and purge oil mist lubrication.

Oil ring -

Oil ring lubrication -

Oil whirl - the turbulent flow of oil in a bearing that can cause instabilities such
as elevated vibration level. It usually occurs in plain journal bearings (or sleeve
bearings) that are lubricated hydrodynamically. The instabilities usually occur at
half the pump running speed.

Open impeller - an impeller with vanes attached to the hub with no front or
back shrouds; the impeller may have small web in-between vanes for structural

Operating region - the flow range in the pump performance curve over which
the pump will operate.

O-ring -

Overfile – see vane overfile.

Overspeed -

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