5.4Connecting the piping
Suction lift lines shall be laid with a rising slope towards the pump and suction head lines with a downward slope towards the pump, to prevent the formation of air pockets.
With short pipelines, the nominal diameters should be at least equal to the nominal diameters of the pump nozzles. For long pipelines, the most economical nominal diameter has to be determined from case to case.
Adapters to larger diameters should have a diffuser angle of approx. 8 in order to avoid any pressure losses caused by the formation of air pockets or gas.
It is recommended to install check and
Caution | Never use the pump itself as an anchorage point |
| for the piping. The |
moments acting on the pump flanges (e.g. due to warped pipelines or thermal expansion) must not exceed the permissible forces and moments.
The pipelines shall be anchored in close proximity to the pump and connected without transmitting any stresses or strains. Their weight must not be carried by the pump.
Caution | If welding work must be performed on the piping |
| when the pump is already installed, the electric |
welding equipment must not be earthed on the pump or baseplate, to prevent current flowing through the rolling element bearings, which could cause their premature destruction (pitting effect).
Thermal expansions of the pipelines must be compensated by appropriate measures so as not to
impose any extra loads on the pump.
Expansion joints may have to be used. An excessive, impermissible increase in the pipeline forces may cause leaks on the pump where the fluid handled can escape into the atmosphere.
Danger to life when hot fluids are handled!
Fig. 9 Max. nozzle forces and moments
Direction of forces:
X= horizontal, parallel to the pump axis
Y= vertical to the pump axis
X= horizontal, at a right angle to the pump axis
Direction of moments:
X= around the horizontal axis, parallel to the pump axis MY = around the vertical nozzle axis
X= around the horizontal axis, at a right angle to the
pump axis
Suction and discharge nozzle are regarded separately.
Multitec
Max. permissible pipeline forces (material codes 10, 11, 12, 13)
Nom. nozzle diameter (DN)
32 50 65 80 100 125 150 200 250
Vertical nozzle, at a right angle to the shaft (N )
Fx | 245 | 510 | 640 | 700 | 1015 | 1470 |
| 1780 | 2700 | - |
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Fy | 410 | 635 | 800 | 970 | 1270 | 1850 |
| 2220 | 3490 | - |
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Fz | 265 | 415 | 520 | 625 | 830 | 1220 |
| 1465 | 2220 | - |
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Horizontal nozzle, at a right angle to the shaft (N ) |
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Fx | 245 | 510 | 640 | 800 | 1015 | 1470 |
| 1780 | 2700 | - |
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Fy | 265 | 415 | 520 | 625 | 830 | 1220 |
| 1465 | 2220 | - |
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Fz | 410 | 635 | 800 | 970 | 1270 | 1850 |
| 2220 | 3490 | - |
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Axial nozzle, parallel to the shaft (N ) |
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Fx | - | - | 800 | - | 1270 | 1850 |
| 2220 | 3490 | 4760 |
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Fy | - | - | 520 | - | 830 | 1220 |
| 1465 | 2220 | 3180 |
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Fz | - | - | 640 | - | 1015 | 1470 |
| 1780 | 2700 | 3810 |
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Moments for all nozzles (Nm ) |
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Mx | 260 | 330 | 460 | 680 | 950 | 1235 |
| 1640 | 2520 | 3580 |
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My | 160 | 250 | 350 | 520 | 715 | 930 |
| 1260 | 1840 | 2710 |
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Mz | 190 | 170 | 240 | 340 | 490 | 660 |
| 840 | 1260 | 1740 |
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Example:
Multitec 50 with radial suction nozzle
-for the suction nozzle, the values given in table column DN80 apply
-for the discharge nozzle, the values given in table column DN50 apply
Max. permissible pipeline forces (material codes 20 to 30)
The values given for material codes 10, 11, 12,13 shall be multiplied by the factor 1.4.
Protection against foreign matter
Before commissioning new installations thoroughly clean, flush and blow through all vessels, pipelines and connections. Often welding beads, scale and other impurities only come off after a certain period of operation. Fit a strainer in the suction line to prevent them from entering the pump. The total
1Strainer housing
2 Fine screen
3 Perforated plate
4 Pump suction nozzle
5 Differential pressure gauge
Fig. 10 Conical strainer for the suction line
9