Saci XV-F Serie Instrucciones De Instalación Y Funcionamiento página 16

XV/XVI/XV-F SS Vertical Multi-stages Centrifugal Pumps
Refer to page 8
4.3 Minimum inlet pressure-NPSH
To avoid cavitation, make sure that there is a minimum pressure on the suction side of the pump.
NPSHA: Net Positive Suction head Available
--The net positive suction head available is a function of the pump
suction system.
NPSHR: Net Positive Suction head required
--The net positive suction head required is a function of the pump
design at the operating point on the pump performance curve.
NPSHA=Ha-Hs-Hf-Hv-Hst (in meters head)
Ha: Barometric pressure.(That can be set to 10.2 m.)
Hs: Suction lift.
Hf: Friction loss in suction pipe.
Hv = KT+KH: Vapor pressure
KT: Flow resistance due to liquid temperature.
KH: Flow resistance due to elevation above sea level.
If the liquid is water, you can consult the tables to determine the
values of KT and KH.
T ( )
20
KT (m) 0.2
H (m) 0
KH (m) 0
Hst: Safety margin. (minimum: 0.5 meters head)
NPSH NPSH : Pump running will be fine.
A R
NPSH NPSH : The pump will be dry running or cavitating.
A R
WARNING
Stop operation of the pump if cavitation occurs. Cavitation will cause pump damage and the resultant damage is not subject to
warranty
4.4 Minimum nominal flow rate
To prevent overheating of the internal pump components, the pump should not be used at flows below the minimum flow rate.
WARNING
Do not run the pump against a closed discharge valve for longer than a few seconds.
The curve below shows the minimum flow rate as a percentage of the nominal flow rate in relation to the liquid temperature..
4.6 Electrical data
See the motor nameplate.
WARNING
Make sure that the supply voltages, phase and frequencies correspond to the motor specifications.
4.7 Number of starts per hour
Motors up to and including 4 kW: Maximum 100 times per hour.
Motors of 5.5 kW and up: Maximum 40 times per
WARNING
If you use another brand of motor then check the manufacturer's instructions for the maximum frequency of starts.
5. Installation
Always refer to the local or national regulations and codes relating to the selection of the installation site, the water and power
connections, etc.
30 40 50
0.4 0.8 1.3
500 1,000 1,500 2,000 2,500 3,000
0.55 1.1 1.65
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
60 70 80
2.2 3.3 5
2.2 2.75 3.3
hour..
15
90 100 110
7.4 11 15
120
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