1. Pacific school of
Engineering , surat A
Presentation on
Cenrifugal pump

2. Guided by MR Vatsal Patel Prepared by:
1} Jogani Ghanshyam ( )
2} Italiya Pratik ( )
3} Kabariya Shubham ( )

3. CENTRIFUGAL PUMP WHAT IS CENTRIFUGAL PUMP?
WORKING MECHANISM OF A CENTRIFUGAL PUMP
ADVANTEGAES AND DISADVANTAGES OF CENTRIFUGAL PUMPS

4. -: Working of Centrifugal Pump :-
Centrifugal pump works on the principle that when a certain mass of liquid is made to rotate along the impeller from the central axis of rotation, it impresses a centrifugal head. It causes the water to move radially outwards at higher velocity and causes the water to rise to a higher level. The motion of water is restricted by casing of pump, it result into pressure build up. In addition , the change in angular momentum of liquid during its fiow reults into increase in pressure head.
The steps involved in operation of centrifugal pump are as follows :
The delivery valve is closed.
The priming of the pump is carried out. Priming involves the filling the liquid in suction pipe and casing upto the level of delivery valve so that no air pockets are left in the system.
if any air or gas pockets are left in this portion of pump, it may result into no delivery of liquid by the pump. A

5. The pump shaft and impeller is now rotated with the help of an external source of power like a motor or any other prime mover.
The rotation of impeller inside a casing full of liquid produces a forced vortex which is responsible in imparting the centrifugal head to the liquid. It creates a vaccum at the eye of impeller and causes liquid to rise into suction pipe from the sump.
The speed of impeller should be sufficient to produce the centrifugal head such that it can initiate discharge from delivery pipe.
Now the delivery valve is opened and the liquid is lifted and discharge through the delivery pipe due to its high pressure.
Thus the liquid is continously sucked from the sump to impeller eye and it is delivered from the casing of pump through the delivery pipe.
Before stopping the pump, it is necessary to close the delivery pipe otherwise the back flow of liquid may take place from the high head reservoir.

6. :Priming of a Centrifugal Pump :
: The operation of filling the casing , impeller and suction pipe and the portion of delivery pump upto delivery valve is called priming.
: In case the priming of pump is not done and the pump is not done and the pump is not under the operation, the water present in the pump and suction pipe will flow back to the sump. The space occupied by water will be filled by air.

7. :- If the pump is now started, the air pockets inside the impeller may give rise to vortices and cause the discontinuity of flow. Under these condition, the flow of fluid does not commence and the pump runs dry. It causes the rubbing and seizing of the wearing rings, increases noise level and vibrations and finally may cause the serious damage to pump. :- The priming in resiprocating pumps is not required since the pumping is done by positively moving the fluid out of the cylinder by the piston. Hence, the air will be displaced from the casing when the pump starts and it will get a suction pressure which will draw the fluid from the sump.

8. Priming for small pumps is done by hand
:- A foot valve is essential at the bottom of suction pipe
:- A funnel or priming cup is provided to fill the water by hand. An air vent is provided in the casing of pump. When the water is filled, the air escapes through the air vent. It is closed once the priming is completed

9. WHAT IS CENTRIFUGAL PUMP ?
Convert the mechanical energy into hydraulic energy by centrifugal force on the liquid
Constitute the most common type of pumping machinery
Used to move liquids through a piping system
Has two main components:
1. Stationary componets, casing, casing cover and bearings
2. Rotating components, impeller and shaft
Classified into three categories ; Radial Flow, Mixed Flow, Axial Flow

10. WORKING MECHANISM OF A CENTRIFUGAL PUMP
Simplest piece of equipment in any process plant
Energy changes occur by virtue of impeller and volute
Liquid is fed into the pump at the center of a rotating impeller and thrown outward by centrifugal force
The conversion of kinetic energy into pressure energy supplies the pressure difference between the suction side and delivery side of the pump
Liquid flow path inside a centrifugal pump

11. ADVANTAGES OF CENTRIGUGAL PUMPS
Simple in construction and cheap
Handle liquid with large amounts of solids
No metal to metal fits
No valves involved in pump operation
Maintenance costs are lower

12. DISADVANTAGES OF CENTRIFUGAL PUMPS
Cannot handle highly viscous fluids efficiently
Cannot be operated at high heads
Maximum efficiency holds over a narrow range of conditions

13. POWER AND EFFICIENCY CALCULATIONS
The power supplied to the pump:
…………(1)
Where m=mass flow rate, kg/s
H= total discharge head, N.m/kg
=efficiency

14. The power delivered to the fluid:
…………(2)
From equations (1) and (2) efficiency:

15. Specific speed that is used to classify pumps
nq is the specific speed for a unit machine that is geometric similar to a machine with the head Hq = 1 m and flow rate Q = 1 m3/s

16. What is a centrifugal pump?
Three basic components:
Volute, casing, body
or Diffuser
Impeller
or impellers
Driver (motor)

17. Pump Impeller
Direction of
rotation
Vanes
Centrifugal Pumps

18. Single suction impeller
Centrifugal Pumps

19. Impeller Types Open Semi-open Closed Single suction Double suction
Non-clogging
Axial flow
Mixed flow
Centrifugal Pumps

20. Generally: Maximum efficiency lies in the range:
2000<NS<3000
High head, low capacity pumps:
500<NS<1000
Low head, large capacity pumps:
NS>15000

21. Full Diameter Impeller
Rotation
Impeller
Blades Vt Vr Vs
Vr = Radial Velocity
Vt = Tangential Velocity
Vs = Vector Sum Velocity
Centrifugal Pumps

22. Impeller and volute Discharge Nozzle Cutwater Suction Eye
Arrows represent the
direction of water flow
Discharge
Nozzle
Cutwater
Suction Eye
Centrifugal Pumps

23. End Suction Pump 26 sizes To 4400 gpm To 520 ft TDH
To 150 HP To 8”x10”
General Purpose Motor
Series 1510
Centrifugal Pumps

24. Double Suction Pump 37 sizes To 12500 gpm To 840 ft TDH To 1000 HP
To 14”x18”
General Purpose Motor
Bell & Gossett
Series HSC
Centrifugal Pumps

25. Typical Split Case Pump- Section View
Centrifugal Pumps

26. Double Suction Pump Series VSC 17 sizes To 8000 gpm Series VSCS
To 400 ft TDH
To 600 HP
To 12”x14”
General Purpose Motor
Series VSCS
Centrifugal Pumps

27. Pump Construction Mechanical seal Internally flushed, seal cavity
Standard construction, any impeller
Mechanical seal
Internally flushed, seal cavity
Variety of seal materials
Stuffing box construction, any impeller
External flush lines
Compression packing rings
Single flushed mechanical seal
Centrifugal Pumps

28. B&G Pump Construction Standard construction, any impeller
Mechanical seal
Internally flushed, seal cavity
Variety of seal materials
Centrifugal Pumps

29. Limits On Seal Performance
Temperature of the flushing water.
225ºF to 250ºF
System pH.
7 to 9 for ceramic seals
up to 11 for tungsten carbide seals
Concentration of dissolved solids.
TDS less than 1000 ppm
Concentration of suspended solids.
Less than 20 ppm
Silica, less than 10 ppm
Centrifugal Pumps

30. Pump Construction Stuffing box construction, any impeller
External flush lines
Internal or External Fluid
Compression packing rings
Single flushed mechanical seal
Centrifugal Pumps

31. What’s “suitable”…? Impeller Volutes
Single suction or double suction.
Volutes
Base mounted or in-line.
Internally flushed or stuffing box.
Single stage or multi stage.
Packing, seal or wet rotor.
Centrifugal Pumps

32. Suction Piping Detail 5 dia. RIGHT WRONG 1. Pipe supported
2. Length of suction piping allows even impeller loading
1. Pipe weight hangs on pump flange.
2. Short suction pipe results in uneven impeller loading.
Centrifugal Pumps

33. Why 5 diameters?
Single Suction
Impeller
Centrifugal Pumps

34. PUMP SELECTION The amount of fluid The properties of the fluid
Type of power supply
Cost and mechanical efficiency of the pump

35. Thanks for listening