A close coupled
centrifugal pump
is identifiable by having a single,
continuous shaft between the
motor and pump, rather than
2 shafts coupled.
Due to the compact design
of a close coupled pump,
you won't easily see the
shaft.
Unlike the screw impeller pump,
the vortex pump does not generate
a centrifugal force. This is because
the impeller is recessed
and therefore outside the
flow region of the volute.
Energy is continuously
generated in the fluid surrounding
the impeller in what is essential
a two-stage pumping process.
Vortex casing is a casing in
which circular chamber is
provided between the casing a
nd the impeller. Vortex casingVortex
casing is a casing in which circular
chamber is provided between the
casing and the impeller.
Vortex casing is helpful to
increase pump efficiency
by reducing eddies formation
to a considerable extent.
Whilst close coupled pumps
benefit from a compact,
cost effective design, they are
less preferable for heavy duty,
high power, continuous use as
there is more strain put on the
common bearings and the size
of the motor is usually limited.
For heavier duty applications,
long coupled pumps are more
suited.
As you can see from figure 2,
centrifugal pumps can be
categorised in different groups
: Radial flow pumps, mixed flow
pumps and axial flow pumps.
Radial flow pumps and mixed
flow pumps are the most
common types used.
A vortex pump (also called a vortex impeller)
is based on the principle of
creating a vortex flow with
a recessed impeller that is
positioned away from the path
of the liquid. The pump creates
a circular churning motion around
an axis to create suction.
The fluid flows into the volute
and out through discharge.
Unlike open impellers,
closed impellers perform
well at a broader range of
speeds but are unsuitable for
pumping solids. If the impeller
becomes clogged, cleaning becomes
difficult. Closed impellers
are mainly used in large-scale
pumps for precise water
applications.
