A mechanical device using suction or pressure to
raise or move liquids, compress gases, or force
air into inflatable objects.
Force (liquid, gas, etc.) to move in a specified
direction by or as if by means of a pump
I. NONPOSITIVE DISPLACEMENT PUMPS
II. POSITIVE DISPLACEMENT PUMPS
A pump produces a force on the liquid that is
constant for each particular speed of the pump.
Resistance in a discharge line produces a force in
the opposite direction
When these forces are equal, a liquid is in a state
of equilibrium and does not flow.
If the outlet of a nonpositive-displacement pump
is completely closed, the discharge pressure will
rise to the maximum for a pump operating at a
This pump, a definite volume of liquid is
delivered for each cycle of pump operation,
regardless of resistance, as long as the capacity of
the power unit driving a pump is not exceeded.
If an outlet is completely closed, either the unit
driving a pump will stall or something will break
Therefore, a positive-displacement-type pump
requires a pressure regulator or pressure-relief
valve in the system.
A centrifugal pump is built up of TWO MAIN
THE ROTOR (or Rotating Element).
THE CASING (or Housing or Body).
Their two parts
THE IMPELLER:-The rotating part of a
compressor or other machine designed to move a
fluid by rotation.
THE SHAFT:- A long, narrow part or section
forming the handle of a tool or club or the body
of a spear or arrow
This is the stationary part of the pump and
includes the :
The act or process of sucking
The force or condition produced by a pressure
difference, as the force holding a suction cap
onto a surface
The act or process of producing such a force or
Discharge pressure describes the pressure of a
liquid as it leaves a pump.
Higher discharge pressures equal greater force
behind the release while lower pressure means
less. A pump’s discharge pressure is influenced.
Pumps are devices that move fluid volume by mechanical or
physical action. Pumps use a particular kind of seal in order to
Bearing is used For reducing friction & driver
torque. For not getting leak also.
Centrifugal pumps, are a sub-class of dynamic
axisymmetric work-absorbing turbomachinery
Centrifugal pumps are used to transport
liquids/fluids by the conversion of the rotational
kinetic energy to the hydro dynamics energy of the
The rotational energy typically comes from an
engine or electric motor or turbine.
In the typical simple case, the fluid enters the
pump impeller along or near to the rotating axis
and is accelerated by the impeller, flowing radially
outward into a diffuser or (volute) chamber
(casing), from where it exits.
A gear pumps which is used as a meshing
gears, to pump the fluid by displacement.
The Gear pumps are also widely used in
chemical installations to pump fluid with a
Gear pumps are positive displacement (or fixed
displacement), meaning they pump a constant
amount of fluid for each revolution.
A liquid ring/Nash pump is a rotating positive
displacement pump. They are typically used as
a vacuum pump but can also be used as a gas
The function of a liquid ring pump is similar to
a rotary vane pump the difference being that the
vanes are an integral part of the rotor and churn a
rotating ring of liquid to form the compression
They are an inherently low friction design, with
the rotor being the only moving part. Sliding
friction is limited to the shaft seals. Liquid ring
pumps are typically powered by an induction
The submersible pumps are multistage
centrifugal pumps operating in a vertical
Roduced liquids, after being subjected to great
centrifugal forces caused by the high rotational
speed of the impeller, lose their kinetic energy
in the diffuser where a conversion of kinetic to
pressure energy takes place.
A pump that raises water by means of helical impellers
in the pump casing.
a hydraulic machine whose working member is a
screw; used for pumping liquids, including highviscosity fluids.
Screw pumps, also referred to as worm pumps, are a
type of rotary pump. The screw pump housing
contains a driving screw and one or two driven screws.
The points of engagement of the screws travel
longitudinally along the shaft during rotation, thus
forcing out the volume of liquid contained between the
turns. It is potential energy that for the most part is
transmitted to the liquids, as a result of which there is a
considerable increase in pressure within it.
A centrifugal pump containing two or more
impellers is called a multistage centrifugal
pump. The impellers may be mounted on the
same shaft or on different shafts.
For higher pressures at the outlet impellers can
be connected in series.
For higher flow output impellers can be
connected in parallel.
All energy transferred to the fluid are derived
from the mechanical energy driving the
A type of hydraulic pump that uses cam lobe
action against pistons to generate hydraulic fluid
A piston pump is a type of positive displacement
pumps where the high-pressure seal reciprocates
with the piston. Piston pumps can be used to
move liquids or compress gases.
The mechanical device that is used to convert
mechanical power into hydraulic energy is known
as a hydraulic pump. The load that is responsible
for the pressure is overcome with this device by
creating sufficient power and generating a flow.
The hydraulic pump has two functions to perform
during operation, allowing atmospheric pressure
to push liquid into the inlet line from the reservoir
to the pump by the mechanical action created
vacuum at the pump. The other function it
performs is that the pumps mechanical action
supplies the liquid to the pump outlet and then
forced into the hydraulic system.
The following graphs address some of the problems that could occur
when a pump is operating:
a. Overloading :- One risk of overloading is the
danger of excess torque on a drive shaft.(You
may need a larger pump)
b. Excess Speed :- Running a pump at too high a
speed causes loss of lubrication, which can cause
Excess speed also runs a risk of damage from
cavitation. (use a higher displacement pump)