Glossary N


ND factor - another name for DN factor. See DN factor.


Net Positive Suction Head Available (NPSHA) - the total absolute suction
pressure, minus the vapor pressure, expressed in the unit of head (feet) of the
pumped liquid, and referred to a datum elevation. The datum elevation is usually
the impeller centerline on a horizontal pump, and either the suction nozzle
centerline or top of foundation on a vertical pump. See NPSHR


Net Positive Suction Head Required (NPSHR) - the net positive suction head
(NPSH) required by a pump without impairing its performance due to cavitation.
Impairment is said to occur when the pump suffers a loss of head equal to 3% of
the head of the first stage impeller at a given flow rate. The NPSHR is usually
referred to the impeller centerline. See NPSHA.


Newtonian liquid - a liquid whose viscosity is independent of the rate of shear at a
given temperature. Shear is the movement of one layer of liquid relative to another
layer when a shearing force is applied. Examples of Newtonian liquids are water
and light oil. See
non-Newtonian liquid.


Nitrogen leak test - see air leak test.

Non-destructive examination (NDE) - (click on link to read full article)


Non-Newtonian liquid - a liquid whose viscosity is dependent on the rate of shear
at a given temperature. Shear is the movement of one layer of liquid relative to
another layer when a shearing force is applied. Examples of non-Newtonian
liquids are paint, grease, molasses, clay slurries, etc. See
Newtonian liquid.


Normal operating point - the point at which the pump operates most of the time,
or under normal operating conditions. This is different from the rated operating
condition which is the point at which the pump performance is guaranteed by the
pump vendor subject to the performance tolerance of the applicable standard or
user specification.


Nozzle head - the part of a vertical barrel pump that contains the suction and
discharge nozzles, and where the driver is mounted. The nozzle head is mounted
on top of the barrel.


NPSHA - see Net Positive Suction Head Available.

NPSHR - see Net Positive Suction Head Required.

NPSHR3 - the net positive suction head required by a pump based on three
percent (3%) head loss.


R: 1111-GLON - glossary N1
C: glossary

Beta version
CENTRIFUGAL-PUMP.ORG
TECHNICAL

Concepts

Parts

Auxiliaries

Glossary

Engineering data

Library

Bulletin board




Go to our Sitemap
for list of articles



By accessing this site
you agree to our
Terms of Use and
Legal Disclaimer



Copyright notice
Privacy policy
Glossary starting with letter:

A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z

A2  B2  C2  D2  E2  F2  G2  H2  I2  K2  L2  M2  N2  O2  P2  R2  S2  T2  U2  V2  W2
Custom Search