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Pacific school of Engineering , surat. A Presentation on. Cenrifugal pump. Guided by. MR Vatsal Patel. Prepared by:. 1} Jogani Ghanshyam (131120131020) 2 } Italiya Pratik (1311201319) 3 } Kabariya Shubham ( 1311201321). CENTRIFUGAL PUMP.

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A presentation on

Pacific school of

Engineering , surat

A

Presentation on

Cenrifugal pump


A presentation on

Guided by

MR Vatsal Patel

Prepared by:

1} JoganiGhanshyam (131120131020)

2} ItaliyaPratik (1311201319)

3} KabariyaShubham(1311201321)


A presentation on

CENTRIFUGAL PUMP

  • WHAT IS CENTRIFUGAL PUMP?

  • WORKING MECHANISM OF A CENTRIFUGAL PUMP

  • ADVANTEGAES AND DISADVANTAGES OF CENTRIFUGAL PUMPS


A presentation on

-: 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 fiowreults 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.


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  • 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.

  • 6. 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.


A presentation on

:Priming of a Centrifugal Pump :

:- 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.

:-The operation of filling the casing , impeller and suction pipe and the portion of delivery pump upto delivery valve is called priming.


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:- 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.


A presentation on

  • 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


What is centrifugal pump

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


Working mechanism of a centrifugal pump

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


Advantages of centrigugal pumps

ADVANTAGES OF CENTRIGUGAL PUMPS

Advantages

  • 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


Disadvantages of centrifugal pumps

DISADVANTAGES OF CENTRIFUGAL PUMPS

Disadvantages

  • Cannot handle highly viscous fluids efficiently

  • Cannot be operated at high heads

  • Maximum efficiency holds over a narrow range of conditions


Power and efficiency calculations

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


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  • The power delivered to the fluid:

…………(2)

  • From equations (1) and (2)efficiency:


Specific speed that is used to classify pumps

Specific speed that is used to classify pumps

nqis 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


What is a centrifugal pump

What is a centrifugal pump?

Three basic components:

  • Volute, casing, body

    • or Diffuser

  • Impeller

    • or impellers

  • Driver (motor)


Pump impeller

Pump Impeller

Direction of

rotation

Vanes

Centrifugal Pumps


A presentation on

Single suction impeller

Centrifugal Pumps


Impeller types

Impeller Types

  • Open

  • Semi-open

  • Closed

    • Single suction

    • Double suction

  • Non-clogging

  • Axial flow

  • Mixed flow

Centrifugal Pumps


Generally

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


Full diameter impeller

Vs

Vr

Vt

Vr = Radial Velocity

Vt = Tangential Velocity

Vs = Vector Sum Velocity

Rotation

Impeller

Blades

Full Diameter Impeller

Centrifugal Pumps


Impeller and volute

Impeller and volute

Arrows represent the

direction of water flow

Discharge

Nozzle

Cutwater

Suction Eye

Centrifugal Pumps


End suction pump

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


Double suction pump

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


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Typical Split Case Pump- Section View

Centrifugal Pumps


Double suction pump1

Double Suction Pump

Series VSC

  • 17 sizes

  • To 8000 gpm

  • To 400 ft TDH

  • To 600 HP

  • To 12”x14”

  • General Purpose Motor

Series VSCS

Centrifugal Pumps


Pump construction

Pump Construction

  • 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


B g pump construction

B&G Pump Construction

  • Standard construction, any impeller

    • Mechanical seal

    • Internally flushed, seal cavity

    • Variety of seal materials

Centrifugal Pumps


Limits on seal performance

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


Pump construction1

Pump Construction

  • Stuffing box construction, any impeller

    • External flush lines

      • Internal or External Fluid

    • Compression packing rings

    • Single flushed mechanical seal

Centrifugal Pumps


What s suitable

What’s “suitable”…?

  • Impeller

    • 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


Suction piping detail

Suction Piping Detail

5 dia.

RIGHT

WRONG

1.Pipe weight hangs on pump flange.

2. Short suction pipe results in uneven impeller loading.

1. Pipe supported

2.Length of suction piping allows even impeller loading

Centrifugal Pumps


Why 5 diameters

Why 5 diameters?

Single Suction

Impeller

Centrifugal Pumps


Pump selection

PUMP SELECTION

  • The amount of fluid

  • The properties of the fluid

  • Type of power supply

  • Cost and mechanical efficiency of the pump


Thanks for listening

Thanks for listening


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