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Fig. 6 Deaeration
Pipe connections
The pipe work shall be installed and supported so that
no pipe stresses are transferred to the pump body.
The pipe forces and torque transferred to the pump
shall be in accordance with ISO 14847. The pipe work
should be tight in order to avoid leakage and infiltration
of foreign particles and/or air. Shut off valves should be
installed in both suction and discharge pipes, so that
the pump can be hydraulically isolated.
Suction line
The suction pipe should be designed so that the total
pressure drop, measured at the pump inlet flange, does
not exceed the suction capability of the pump. Make a
proper calculation of the suction line including compo-
nents such as valves, strainer, pipe bends etc. Gener-
ally, the pressure drop in the suction line should be as
low as possible, which is achieved if the suction pipe is
short, straight and has a suitable diameter. The velocity
in the suction line should be kept in the range
0.5 - 1.2 m/s. For L.O. circulating systems, we recom-
mend to keep it as low as possible. The suction line
must be equipped with a port that allows filling the
pump before start.
Discharge line
The discharge line should be dimensioned to keep the
velocity in the range 1 - 3 m/s.
Deaeration
In installations with negative suction head, where the
pump might be started against a pressurized system, a
deaeration pipe with an orifice (2-3 mm is recommend
-
ed) has to be installed. The deaeration pipe should be
connected to the outlet pipe’s highest point. This must
also be installed when the pump is used as a stand-by
pump.
Liquid trap
In some mounting arrangements the pump may not
retain the liquid at stand still. In such installations the
suction pipe should be arranged so it forms a liquid trap
together with the pump, keeping the pump half filled
with liquid.
Fig. 4 Pipe connections
Fig. 5 Suction Line
16
When handling liquids that may harm skin
use gloves and/or protective clothing
17
When handling liquids shich may involve
fire hazards appropriate precautions to
avoid danger are to be taken.
Fig. 7 Liquid trap
