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A Presentation on

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

  2. Guided by MR Vatsal Patel Prepared by: 1} JoganiGhanshyam (131120131020) 2} ItaliyaPratik (1311201319) 3} KabariyaShubham(1311201321)

  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 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.

  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. • 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.

  6. :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.

  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 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

  12. 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

  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 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

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

  22. Impeller and volute 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 • To 400 ft TDH • To 600 HP • To 12”x14” • General Purpose Motor Series VSCS Centrifugal Pumps

  27. 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

  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 • 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 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

  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

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