29-04-2014, 12:29 PM
Pumps
Pumps[.pdf (Size: 533.11 KB / Downloads: 18)
SUMMARY
From start to finish, pumps play an important role in all water distribution systems. They are used
to transfer raw water to the treatment plant; they supply water to sections of a distribution system
where it is not possible to supply it by gravity; they add appropriate chemical doses during treat-
ment; and they transfer sludge from settling chambers for further treatment and disposal.
Pump Applications
Different types of applications require differ-
ent types of pumps. Pumps are selected
based on system requirements, discharge
pressure required, flow capacity required,
and availability of space. The two most com-
mon pumps in the water industry are: cen-
trifugal pumps, used most often in water
distribution, and positive-displacement
pumps, most commonly used in treatment
plants for chemical dosing.
Because centrifugal pumps are so widely
used in water distribution and because so
many brands are available, the individual
procedures for proper operation vary. Most
manufacturers supply instructions, guidelines,
or manuals with a new pump. Users must fol-
low these instructions while operating pumps.
Pump Starting and Stopping
During pump startup, check the lubrication
of the motor bearings and prime the pump.
After priming, the pump must be started
with the discharge valve fully closed. The
discharge valve must then be opened slowly
to allow any air in the system to escape. The
pump discharge valve must be opened and
closed slowly to prevent water hammer in
the system. (For more information about
water hammer, see the Tech Brief in the
Winter 2003 On Tap.)