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Installation
The diameters of the pipes, valves and fittings must be calculated according to the expected head losses in the installation
and in such a way that the fluid velocities are:
•
Velocity in delivery pipe: 2 to 3 m/s.
•
Velocity in suction pipe: 1 to 2 m/s.
To avoid pump cavitation, the available NPSH of the suction piping system must be higher than the NPSH required by the
pump. This is achieved by lowering the head loss of the suction piping, increasing its diameter, minimum possible length,
minimum number of fittings, not exceeding the required flow rate, low temperature (minus 33ºC if water, minimum negative
head and even better if the suction is positive.
If a long suction line is required, it should be installed with a continuous elevation slope in the direction of the pump and
without high points, to avoid the accumulation of air pockets, see figure 9.
Figur
e
8
Figur
e
9
If a reduction is installed in the suction line, it must be eccentric and its straight part must be at the top, to facilitate
the exit of trapped air bubbles to the pump, see figure 9.
Figur
e
10
10 x 0
0
The elbows and fittings installed on the pump suction must be selected and installed in such a way that the liquid
enters the impeller in a symmetrical and orderly manner, this is achieved by installing a section of pipe of the same
diameter as the pump suction and a length of 10 times that diameter,
f
igure 10.
Installation
