TFD - Pump Types 2
Classification of Pumps
q The hierarchy of pump classification is as follows
§ The way the energy is added to the fluid
• Kinetic / Dynamic Pumps adds energy continuously
• Positive Displacement Pumps adds energy periodically
§ The way this principle (addition of energy) is implemented
• Kinetic Pumps
• Centrifugal
• Special Effect
§ Delineation of specific geometries
• Positive Displacement
• Reciprocating
• Rotary
• Kinetic Pumps
• Centrifugal
– Axial
– Mixed Flow
– Radial
• Positive Displacement
• Reciprocating
– Piston
– Diaphragm
• Rotary
– Single rotor
– Multiple Rotor

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TFD - Pump Types 3
Kinetic (Dynamic) Pumps
KINETIC PUMPS
CENTRIGUGAL PERIPHERAL
Radial
Mixed
Regenerative
SPECIAL
Axial
Viscous Drag
Eductor/Ejector
Electromagnetic
Impellers are
classified
according to
the major
direction of
flow in
reference to
axis of
rotation
q Kinetic pumps add energy continuously to increase the
fluid velocity (kinetic energy) within the pump element
such that subsequent velocity reduction in pump volute
produces a pressure increase (potential energy).

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Centrifugal Pump
Operating Principle
q A centrifugal pump is one of the simplest pieces of
equipment in any process plant.
q Its purpose is to convert energy of a prime mover (an
electric motor or turbine) first into velocity or kinetic
energy and then into pressure energy of a fluid that is
being pumped.
q The energy changes occur by virtue of two main parts of
the pump, the impeller and the volute (or diffuser).
§ The impeller is the rotating part that converts driver energy into
the kinetic energy.
§ The volute or diffuser is the stationary part that converts the
kinetic energy into pressure energy.

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TFD - Pump Types 5
Centrifugal Pump
Operating Principle
q The centrifugal pumps utilize one
pumping principal: The impeller increases
the kinetic energy of the fluid by
accelerating it from the impeller center out
to the tip.
§ The impeller tip speed largely determines the
pressure generated by a pump
§ Tip Speed = pi * Tip Dia (OD) * (RPM / 60)
q At the periphery of the impeller exit the fluid
is directed into the pump casing (volute).
q The volute has a constantly increasing cross
sectional area along its length.
q As the fluid proceeds along the volute
channel its velocity is reduced as a result
the pressure of the fluid increases.

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TFD - Pump Types 6
Centrifugal Pump
Operating Principle
q The key idea is that the energy created by the centrifugal force is
kinetic energy.
q The amount of energy given to the liquid is proportional to the
velocity at the edge or vane tip of the impeller.
§ The faster the impeller revolves or the bigger the impeller is, (higher
the tip speed) then the higher will be the velocity of the liquid at the
vane tip and the greater the energy imparted to the liquid.
q This kinetic energy of a liquid coming out
of an impeller is harnessed by creating a
resistance to the flow.
§ The first resistance is created by the pump
volute (casing) that catches the liquid and
slows it down.
§ In the discharge nozzle, the liquid further
decelerates and its velocity is converted to
pressure according to Bernoulli’s principle.

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TFD - Pump Types 7
A Pump Fact…
One fact that must always be remembered:
A pump does not create pressure,
it only provides flow.
Pressure is a just an indication of
the amount of resistance to flow.

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TFD - Pump Types 8
Single & Double Suction Impellers
q Double suction pumps are used
to increase the capacity of the
pump for a given space.
§ Most widely used through out
the industry.
§ Low initial cost
§ High efficiency and low NPSH for
flow rates above 700-1000 GPM.
• Lower inlet velocity due to
increased (doubled) inlet flow
area.
q Double suction pumps can be
quite large, pump high capacities
and can handle entrained gas or
air.
Single
Suction
Impeller
Double
Suction
Impeller

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TFD - Pump Types 9
Centrifugal Pump
Single or Multi Stage
q Centrifugal pumps maybe
single stage having a single
impeller.
q They may be multiple stage
having several impellers
through which the fluid flows
in series.
q Each impeller in the series
increases the pressure of fluid
at the pump discharge.

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TFD - Pump Types 10
Centrifugal Pump
Open or Closed Blades
q The impeller of a centrifugal pump can be
§ open, close or semi-open
q In a closed design there’s a shroud over the blades that
covers the top of the impeller.
q In an open design there’s no material between the top of
the blades and housing.

and...

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