pump and its classifications centrifugal pump and its classification and working and advantages and disadvantages and applications of centrifugal pump

1. Applied Hydraulics
TOPIC:
CENTRIFUGAL PUMPS
COMPILED BY:
TALHA HUSSAIN (17CE11)

2. What is a pump?
 Pumps are machines which supply energy to a liquid in order to
move it from place to another.
 A pump provides energy to a fluid in a fluid system by
converting mechanical energy to increase the pressure energy
or kinetic energy , or both of the fluid.
 A hydraulic pump is a mechanical device that converts
mechanical power into hydraulic energy.

3. Pumps are used to increase
1. Velocity (flow rate) of liquid
2. Pressure of liquid
3. Elevation of liquid

4. Pumps enable a liquid to
 Flow from low pressure to one of high pressure
 Flow from a low level to a higher level
 Flow at a faster rate

5. Difference between pump and turbine
 In the turbine flow takes place from the high
pressure side to the low pressure side
 Whereas in pump flow takes place from the low
pressure towards the higher pressure
 Thus in a turbine there is accelerated flow, while in a
pump, the flow is decelerated

6. Classification of Pumps
On the basis of transfer of mechanical energy pumps
are classified as follows:
1. Rotodynamic pump
2. Positive displacement pump

7. Rotodynamic pump
 In rotodynamic pumps, increase in energy level is
due to a combination of centrifugal energy, pressure
energy and kinetic energy.
There are three types of rotodynamic pump:
 Radial flow pump
 Axial flow pump
 Mixed flow pump

8. The energy transfer, in a radial flow pump, occurs mainly when
the flow is in its radial path. The radial flow type pumps are
commonly called centrifugal pumps.
In an axial flow pump, the energy transfer occurs when the flow is
in its axial direction.
The energy transfer in a mixed flow pump takes place when the
flow comprises radial as well as axial components.

9. Positive displacement pump:
 Positive displacement pump apply pressure directly
to the liquid by a reciprocating piston.

10. Centrifugal Pump
 A centrifugal pump is rotating machine in which flow
and pressure are generated dynamically.
 It works on the principal of centrifugal force.
 Flow is in radial outward direction.

11. Classification of centrifugal pumps
On the basis of characteristic features, the centrifugal pumps are
classified as follows:
1. Type of casing:
(i) Volute pump
A volute is a curved funnel that increases in area as it
approaches the discharge port. The volute of a centrifugal
pump is the casing that receives the fluid being pumped by
the impeller, maintaining the velocity of the fluid through to the
diffuser. As liquid exits the impeller it has high kinetic energy
and the volute directs this flow through to the discharge.

12. (ii) Turbine pump or diffusion pump
Diffusion pumps use a high speed jet of
vapor to direct gas molecules in the pump
throat down into the bottom of the pump
and out the exhaust.

13. 2. Working head:
(i) Low lift centrifugal pump:
They work against heads up to 15 m
(ii) Medium lift centrifugal pumps:
They are used to build up heads as high as 40 m
(iii) High lift centrifugal pumps:
They are employed to deliver liquids at heads above 40 m.

14. 3. Liquid handled:
(i) Closed impeller pump
(ii) Semi-open impeller pump
(or Non-clog pump)
(iii) Open impeller pump.

15. 4. Number of impellers per shaft:
(i) Single stage centrifugal pump: It has
one impeller, usually a low lift pump.
(ii) Multi- stage centrifugal pump:
It has two or more impellers and pressure is
built insteps; used usually for high working
heads and the number of stages depends
on the head required.

16. 5. Number of entrances to the impeller:
(i) Single entry or single suction pump: In
type of pump water is admitted on one side
of the impeller.
(ii) Double entry or double suction pump: In
this type of pump water is admitted from both
sides of the impeller; axial thrust is neutralized.
These types of pumps are employed for
pumping large quantities of fluid.

17. 6. Relative direction of flow through impeller:
(i) Radial flow pump: In these pumps normally radial flow
impellers are used in all centrifugal pumps
(ii) Axial flow pump: these are designed to deliver huge quantities
of water at comparatively low heads; ideally suited for irrigation
purposes.
(iii) Mixed flow pump: these are mostly employed for irrigation
purpose

19. Parts of a Centrifugal Pump
1. Impeller
2. Casing
3. Suction pipe
4. Delivery pipe

21.  1. Impeller. An impeller is a wheel (or rotor) with a series of backward curved vanes (or blades). It is
mounted on a shaft which is usually coupled to an electric motor.
 2. Casing. The casing is an airtight chamber surrounding the pump impeller. It contains suction and
discharge arrangements, supporting for bearings, and facilitates to house the rotor assembly. It has
provision to fix stuffing box and house packing materials which prevent external leakage.
 3. Suction pipe. The pipe which connects the centre/eye of the impeller to sump from which liquid is to
be lifted is known as suction pipe.
 4. Delivery pipe. The pipe which is connected at its lower end to the outlet of the pump and it delivers
the liquid to the required height is known as delivery pipe.
Parts of a Centrifugal Pump

22. Working of centrifugal pump
 A centrifugal pump works on the principal that when a certain
mass of fluid is rotated by an external sources it is thrown away
from the central axis of rotation and a centrifugal head is
impressed which enables it to rise to a higher level.

23. Working of centrifugal pump (cont.)
 In other words impeller in rotating motion forces water out
towards the circumference due to centrifugal force effects.
 Due to this, negative pressure gets generated at the center
of the pump so water is sucked from the sump via suction
pipe which is connected to the pump.
 The kinetic energy of high velocity water is converted into
pressure energy because of diverging passage of casing.

25. Advantages
 Small in size and space saving
 Output is consistent
 Easy for maintenance
 No danger creates if discharge valve is closed while starting
 Deal with large volume
 Able to work on medium to low head
 Able to work on medium to low viscous fluid
 Almost no noise

26. Disadvantages
 Extra priming process requires
 Cannot be able to work on high speeds
 Cannot deal with highly viscous liquid

27. Applications
 Agriculture and irrigation purpose
 Pumping of water in buildings
 Transfer raw material

28. Thank You