1. Pumps
Basic Terms Definition Types Principal of Operation
Major components & their Function Terminology
-Dhulasi Vinothini K.S
2. What is Pump?
Pump: It is a mechanical device used to convert mechanical
energy into hydraulic energy in terms of pressure energy, When a
fluid has to be "moved" in a system, pumps are used. The pump
is a machine which has the function of increasing the total energy
of a liquid; this means that the pump transfers energy to the fluid
that it receives from the driving motor”.
Need Of a Pump:
Used to pump a liquid from lower pressure area to a High
pressure area.
To increase Flow rate.
To move liquid from lower elevation to higher elevation.
4. Positive Displacement Pumps
Working Principle:
Positive Displacement Pump has an expanding
cavity on the suction side of the pump and a decreasing cavity on
the discharge side. Liquid is allowed to flow into the pump as the
cavity on the suction side expands and the liquid is forced out of
the discharge as the cavity collapses.
5. 1. Rotary-Type Positive Displacement
Pump
It works on rotary mechanism in the rotating part
which induces vaccum pressure to pull up the liquid from the
suction side. It is the rotation which displaces the fluid from
reservoir to the discharge pipe. The common example of these
types of pumps are: internal gear, screw pump, flexible vane or
sliding vane, flexible impeller, circumferential pump, helical
twisted roots etc.
7. Applications Of Rotary Pump
• Refrigeration Heating and Air Conditioning.
• High viscosity or metering- Lobe-type, flexible-vane or screw
pump
• High density stocks such as Paper and pump, chemical
Transfer and metering-Screw pump
• Sewage Treatment plants for transfer of concentrated sludge
and scum
• Water Supply and carbon slurry pump.
8. 2. Reciprocating Types Positive
Displacement Pumps
In these pumps, there is a reciprocating part
(which moves backward and forward) to pump the water. The
reciprocating parts may be of plunger, piston or diaphragm type.
It contains valves, inlet valves and outlet valves. The inlet valves
open and outlet valves remain closed during suction of liquid.
And inlet valves remain closed and outlet valves gets open during
discharge of the liquid.
13. DYNAMIC PUMPS
1.CENTRIFUGAL PUMP:
Major Parts:
• Shaft: It transmit the torque/Power, supporting the impeller and
other rotating parts.
• Impeller: An Impeller has vanes that pushes the liquid through
the impeller. Transmit energy into the fluid (hydraulic energy).
• Volute/Casing: Impeller are fitted inside the casing. Volute
casing is a curved shaped ,increasing in cross sectional area.
Volute reduces the velocity of the liquid and increases the
pressure
14.
15. Working mechanism:
1. As normal the vaccum pressure induced by the
rotation of the impeller pulls the liquid and induces
kinetic energy to the fluid
2. By Continuity equation,
ρ AV=constant , As area increases velocity
decreases and kinetic energy also increase
3. By Bernoulli’s Equation, it increases the Pressure in
the discharge side to push the liquid.
17. NPSH
What is NPSH?
The difference between inlet pressure and the lowest
pressure level inside the pump is called NPSH: Net Positive
Suction Head. NPSH is therefore an expression of the pressure
loss that takes place inside the first part of the pump housing.
NPSH Available (NPSHA): a measure of how close the fluid at a
given point so to cavitation.
NPSH Required (NPSHR): The minimum pressure required at
the suction port of the pump to keep the pump from cavitation.
18.
19. Displacement Vs Centrifugal
POSTIVE DISPLACEMENT
PUMPS
CENTRIFUGAL PUMPS
1) High Head 1) Low head
2) Low flowrate 2) High Flowrate
3) High viscosity
applications.
Includes a relieve valve in
these pumps.
3) low viscosity applications
as viscosity increases its flow
decreases.
4) High pressure applications
as it maintains constant
flowrate even if the pressure
changes
4) Low pressure applications
as change in pressure varies the
flowrate.
