Seko 43651 Manuel D'installation page 8

Q Portata
Q Portata media
A
Q Portatamassima
M
a Corsa di scarico
b Corsa di aspirazione Carrera de aspiración Suction stroke
t Tempo
2.4 Discharge line (see installation recommendations table)
• Verify that between suction and discharge there is a positive pressure of at least 50÷ 100 Kpa; if the plant con-
ditions don't permit a positive pressure difference, install a back pressure valve on pump discharge (fig. 6) or
lower suction tank (fig. 7) or raise discharge pipe (fig. 8)
• For safety reasons it is mandatory to install a pressure relief valve in order to prevent dangers as consequence
of unexpected overpressure; the pressure relief valve discharge should be visible and/or piped back to the tank
or to a drain.
We do not recommend to pipe the pressure relief valve discharge to the pump suction line (fig. 9).
• In case a back pressure valve is installed the pressure relief valve must be installed as shown in fig. 10.
• It is recommended the installation of pressure gauges having a range of 20% higher than the pressure relief
valve setting.
• To reduce flow pulsation, the installation of a pulsation damper near the discharge valve of the pump is highly
recommended.
The most used dampers are:
• dampers with direct contact between process liquid and gas/air cushion (air chamber); this type is of simple
concept but it needs frequent checks and restoring of the atmospheric air cushion.
• dampers with diaphragm or bag which separates gas/air from process liquid; they are generally precharged at
a pressure equal to 60÷75% of the maximum operating pressure of the pump when installed on the discharge
side of the pump.
These dampers require periodic checks to verify diaphragm/bag integrity and correct precharge pressure; they must
be selected considering the chemical compatibility of the construction material of diaphragm/bag.
If the pump discharges into a pressurized line, the installation of a non-return valve is recommended.

When installing pump and accessories it is recommended the installation of check valves in order to facilitate
maintenance operations. Fig. 13 shows a typical installation.

Please observe the following instructions when pumping liquids that tend to cristallize or suspensions that
tend to sediment:
•
keep suspension correctly agitated in order to prevent sedimentation
•
avoid installation of vertical lines over the pump discharge nozzle
•
before stopping the pump start a washing cycle of the pump and pipes
•
design suction and discharge lines should permit complete emptying
SPR0136001
Q
a
b
Fig. D
Caudal Flow rate
Caudal promedio Medium Flow rate
Caudal máximo Maximum flow rate Débit maximale
Carrera de impulsión Discharge stroke
Tiempo Time
Rev. 5.2
Q = 3,14 x Q
M A
Q
M
Q
A
t
Débit
Débit moyen
Course de refoulement Auslaßhub
Course d'aspiration
Temps
EN
Förderleistung
Duchschnittliche
Max.
Durchflussmenge
Ansaughub
Zeit
6