JV, JVI, JVN Vertical Multistage Centrifugal Pump ... - Javelin Pumps
JV, JVI, JVN Vertical Multistage Centrifugal Pump ... - Javelin Pumps
JV, JVI, JVN Vertical Multistage Centrifugal Pump ... - Javelin Pumps
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Minimum inlet pressure NPSH<br />
If the pressure in pump is lower than the vapour<br />
pressure used to convey liquid, cavitation will occur. To<br />
avoid cavitation, a minimum pressure at the inlet side of<br />
the pump shall be guaranteed. The maximum suction lift<br />
can be calculated with following formula:<br />
H = Pb x 10.2 - NPSH - Hf - Hv - Hs<br />
Pb = atmosphere pressure [bar] (can be set as 1 bar)<br />
In a closed system, Pb means system pressure [bar]<br />
NPSH= Net positive suction head [m], It can be read out<br />
from the point of possible max. flow rate shown on<br />
NPSH curve<br />
Hf = Pipeline loss at the inlet [m]<br />
Hv = Steam pressure [m]<br />
Hs = Safety margin Minimum 0.5m delivery head<br />
If the calculated result H is positive, the pump may run<br />
under the max. suction lift H. In case the calculated<br />
result H is negative, a delivery head of min. inlet pressure is<br />
necessary.<br />
Operation Operation in in parallel parallel<br />
- Connecting several pumps in a parallel running mode will<br />
benefit the reliability of the system compared to a single<br />
pump system.<br />
- Applicable to different working states required by a variable<br />
flow system.<br />
- Increasing the availability of water supply if a pump fails:<br />
only a part of the system flow is affected.<br />
G E N E r A l D A t A<br />
Check and ensure that the pump is not at cavitation<br />
state.<br />
Two pumps or more can be connected in parallel<br />
running if necessary.<br />
10 J AV E L I N - V E R T I C A L M U LT I S TA G E C E N T R I F U G A L P U M P S