2. INDEX
PRIMING
MULTISTAGE CENTRIFUGAL PUMP
PARALLEL ARRANGEMENT
CAVITATION
EFFECT OF CAVITATION
OPERATING CHARACTERISTICS
SELECTION OF CENTRIFUGAL PUMP
3. PRIMING
It is the process of filling suction pipe, casting
and delivery pipe upto delivery valve with water.
Used to remove air from these parts.
It is of two types:
a) Positive Priming:- The one which speeds up
processing.
b) Negative Priming:- The one which slows down
the processing.
4. MULTISTAGE CENTRIFUGAL PUMP
It consists of two or more impellers.
There are two types as follows
a) SERIES: To produce high head.
b) PARALLEL: To discharge large quantity of liquid.
6. CAVITATION
It is a phenomena of formation of vapour
bubble where the pressure falls below the
vapour pressure of flowing liquid.
Collapsing of vapour bubble causes high
pressure results in pitting action on metallic
surface.
Erosion, noise & vibration are produced.
8. EFFECT OF CAVITATION
o Metallic surface are damaged & cavities are
formed.
o Efficiency of pump decreases.
o Unwanted noice and vibrations are produced.
9. CHARACTERISTICS CURVE
These are required to predict the performance &
behaviour of pump working under different head,
flow rate & speed.
Following are the important curves:
a. Main characteristics curve.
b. Operating characteristics curve.
c. Muschel or constant efficiency curve.
11. SELECITON OF CENTRIFUGAL PUMP
(BASED ON SPECIFIC SPEED)
S.NO. SPECIFIC SPEED TYPE OF CENTRIFUGAL PUMP
1 10 to 30 Slow speed pump, with radial flow at outlet.
2 30 to 50 Medium speed pump, with radial flow at outlet.
3 50 to 80 High speed pump, with radial flow at outlet.
4 80 to 160 High speed pump, with mixed flow at outlet.
5 160 to 500 High speed pump, with axial flow at outlet.
6 Above 500 Very high speed pump.
