A multi-stage centrifugal pump
When the liquid enters the pump-casing, the impeller (fed by the motor) projects
the fluid to the periphery of the pump-casing in virtue of the centrifugal force
produced by the impeller's speed: in this way the liquid stores (potential)
energy that will be transformed into flow rate and head (or kinetic energy).
This centrifugal movement simultaneously creates a vacuum capable of sucking the
fluid to be pumped. Then the liquid is easily channeled by connecting the pump
with the discharge piping, leading to the pump exterior. The impeller of a
centrifugal pump can be built according to many constructive variations: open
impellers, closed impellers, single-channel impellers, single channel impeller,
axial impellers, semi-axial impellers, semi-open vortex impellers, semi-open
vortex impellers, spiral impellers, etc.
Centrifugal pumps may be
single-stage, that is having only one flow and pressure generator (an impeller).
A multi-stage centrifugal pump instead has more than one impeller (the first
impeller discharges the liquid to the second and so on) and is characterized by
the sum of the pressures delivered by each impeller. In addition to the initial
priming action, the operation of a centrifugal pump also depends on the way in
which the liquid suction itself is achieved: if in fact the pump is located
below the vein from which it draws the liquid, the liquid spontaneously enters
the pump (this is flooded installation). Whereas if the pump is located above
the source to be pumped, then the liquid will have to be sucked: hence the pump
(as for suction piping) must fore first be primed, i.e. filled with liquid (a
self-priming pump will be used).
A centrifugal system has innumerable
advantages as compared with other types of pumping: it ensures small clearance
volumes, relatively silent service and easy operation with all types of
electrical motors available on the market. It can also easily adapt to all
liquid treatment problems in so far as, by adjusting to the particular
conditions of use, it can meet the specific needs of the facilities where it
will be used.
More products of pumps
Pneumatic and electric diaphragm pumps
2012-05-25
