A pump is a machine for raising a liquid to a higher level of pressure or head. In general pumps may be defined as a mechanical device which when connected in a pipeline, converts the mechanical energy into hydraulic acting on the fluid.## Mechanical Engineering FOR (EEE)

1. PUMP
(CENTRIFUGALAND RECIPROCATING)
Presented By
Md.Meshkat Hasan
Department of EEE, DIU

2. BASICS OF PUMP :
Reference Video: https://www.youtube.com/watch?v=ghiH216pBHQ

3. PUMP :
⮚A pump is a machine for raising a liquid to a higher level of pressure or head. In general pumps
may be defined as a mechanical device which when connected in a pipeline, converts the
mechanical energy into hydraulic acting on the fluid. Thereby increasing the energy of flowing
fluid. Normally pumps are used to transfer liquid from one place to another as well as lower level
to higher level. Pumps broadly classified into two
✔1. Positive displacement pumps (Reciprocating Pump)
✔2. Rotodynamic pumps (Centrifugal Pump)
Reference Video:
https://www.youtube.com/watch?v=FPXIeehl0M8

4. CENTRIFUGAL PUMP
⮚The centrifugal pump defines as a hydraulic machine which
converts the mechanical energy into hydraulic energy by means of a
centrifugal force acting on the fluid.
⮚In this, the pump uses a centrifugal force acting on the fluid surface
to convert the mechanical energy. The centrifugal pump flows in a
radial outward direction. therefore the pump acts like a
reverse reaction turbine. These pumps are using to raises the water or
liquid from a lower level to a higher level.

5. PARTS OF CENTRIFUGAL PUMP
The different parts of the centrifugal pump are listed below.
✔Shaft
✔Impeller
✔Casing
✔Suction Pipe
✔Delivery Pipe
1. Shaft
❑ It is a central part of the pump which is rotating with the impeller is connected.
❑ The shaft coupled to the prime mover to get the power.
❑ The shaft fits with the ball bearing.

6. PARTS OF CENTRIFUGAL PUMP
2. Impeller
❑ It is consist of a series of backward curved vanes.
❑ It is mounted to the shaft of an electric motor.
❑ An impeller is a rotating part of the centrifugal pump.
❑ It enclosed in a watertight casing.
3. Casing
❑ It is an airtight passage surrounding the impeller.
❑ It is designed in such a way that the kinetic energy of the water discharged at the outlet is converted
into pressure energy before the water leaves the casing and enters the delivery pipe.
❑ The casing works as a cover to protect the system.

7. PARTS OF CENTRIFUGAL PUMP
4. Suction Pipe with a Foot Valve and Strainer
❑ The suction pipe has two ends.
❑ One end is connected to the inlet of the pump and the other dips into the water in a sump.
❑ A foot valve fits at the lower end of the suction pipe. The foot valve is the one-way type
of valve which only opens in an upward direction.
❑ A strainer is also fitted at the end of the suction pipe to prevent the entry of foreign bodies
into the suction pipe.
5. Delivery valve
❑ The delivery valve has two ends.
❑ One end is connected to the outlet of the pump and the other end delivers the water at a
required height.

9. PARTS OF CENTRIFUGAL PUMP

11. WORKING PRINCIPLE OF
CENTRIFUGAL PUMP
❑The pump works on the principle of the forced vortex flow. it means when a mass
of liquid is rotating by an external torque, the rise in pressure head of the rotating
liquid takes places. The rise in pressure head is more at the outlet of the impeller
and the liquid will discharge with a high-pressure head at the outlet. Due to this,
the high-pressure head of the liquid can be lifted to a high level. This pump is
suitable for low head discharge. It develops normally at the head of 50m.
❑The first step is priming. It is the operation in which suction pipe, casing of pump
and portion of delivery tube are completely filled with the liquid which is to be
pumped, so that all the air from this portion of the sump is driven out and no air
pocket is left. If there is any air pocket, it result in no delivery of liquid from
pump.

12. WORKING PRINCIPLE OF
CENTRIFUGAL PUMP
❑If the air is not removed from the pump then only a small negative pressure is
created at the suction pipe and it cannot suck the water from the water sump.
❑While in reciprocating pump the suction pressure is created by the movement of
the plunger or the piston so there is no need of priming.
**The necessity of priming a centrifugal pump is due to the fact that the pressure
generated in a centrifugal pump impeller is directly proportional to the density of
fluid. After the pump is primed, electric motor started to rotate the impeller. Due to
rotation impeller rotation, produces a vortex which imparts a centrifugal head to
liquid. Then the liquid starts to flow in an outward radial direction thereby leaving
the vanes of impeller. At the center of impeller a partial vacuum is created , causes
the liquid from sump or well to rush through suction pipe to the eye of impeller.**
MustWatch : https://www.youtube.com/watch?v=Omybiej3IT8

13. RECIPROCATING PUMP:
⮚Reciprocating pump is a device which converts the mechanical energy into hydraulic energy by
sucking the liquid into a cylinder. In this pump, a piston is reciprocating, which uses thrust on the
liquid and increases its hydraulic energy.
⮚Reciprocating pump is also known a called a positive displacement pump.

14. MAIN PARTS OR COMPONENTS
RECIPROCATING PUMP
A reciprocating pump consists of several parts and those are:
❖ Suction Pipe
❖ Suction Valve
❖ Delivery Pipe
❖ Delivery Valve
❖ Cylinder
❖ Piston and Piston Rod
❖ Crank and Connecting Rod
❖ Strainer
❖ Air Vessel

15. WORKING PRINCIPLE OF A RECIPROCATING
PUMP WITH DIAGRAM:
❑This type of pump is consists of a piston that moves forward and backward in a close-fitting cylinder.
The movement of the piston is obtained by connecting the piston rod to crank by means of a
connecting rod. The crank is rotated by means of an electric motor.
❑Suction and Delivery Pipes with a suction valve and a delivery valve are connected to the cylinder.
The suction and delivery valves are non return valves, which allow the water to flow in one direction
only.
❑The suction valve allows water from the suction pipe to the cylinder and where the delivery valve
allows water from the cylinder to the delivery pipe only.
❑When the crank starts rotating, the piston moves in the cylinder.
❑From the above diagram, When a crank is at A, the piston is at the extreme left position in the cylinder.
As the crank is rotating from A to C,(θ=0º to 180º) the piston is moving towards the right in the
cylinder.

16. WORKING PRINCIPLE OF A RECIPROCATING
PUMP WITH DIAGRAM:
❑The movement of the piston towards the right creates a partial vacuum in the cylinder. But on the
surface of the liquid in the sump atmospheric pressure is acting, which is more than the pressure
inside the cylinder.
❑Thus the liquid is forced into the suction pipe from the sump. This liquid opens the suction valve
and enters into the cylinder.
❑When a crank is rotating from C to A (θ=180º to 360º), the piston from the extreme right position
starts moving toward left in the cylinder.

17. WORKING PRINCIPLE OF A RECIPROCATING
PUMP WITH DIAGRAM:

18. DIFFERENCE BETWEEN CENTRIFUGAL
PUMPAND RECIPROCATING PUMP
✔The centrifugal pump is simple in construction than the reciprocating pump. Because the
centrifugal pump has less number of parts.
✔Centrifugal pump has more weight due to a given discharge. Where reciprocating pump has less
weight of pump for a given discharge.
✔Centrifugal pumps are suitable for large discharge with a small head. Where reciprocating pumps
are suitable for less discharge with a high head,
✔Centrifugal pump requires more floor space and heavy foundation. The reciprocating pump
requires less floor space with a simple foundation.
✔Centrifugal pump has less wear and tear compare to reciprocating and it can handle dirty water.
✔Centrifugal pump delivery is continuous and needs priming. Whereas reciprocating pump delivery
is pulsating and no needs priming.

19. Thank You