Different types of water pump

This presentation will provide knowledge on different types of water pump. Working mechanism of each pump is described effectively with advantages and disadvantages of each.

1. Different types of Water pump Vijitha Vikneshwaran Lecturer (Temporary) Faculty of Technology University of Jaffna

2. Diaphragm Piston Plunger Reciprocating Rotary Mixed flow Gear Lobe Sliding Vane Screw Axial flow Centrifugal Rotodynamic Turbine Positive displacement PUMP 2 2 Types of pumps

3. Types of pumps, cont …. Figure 01: Rotodynamic pump Figure 02: Positive Displacement pump 3

4. Rotodynamic pump It has a rotating element which rotates in a casing and imparts energy to water. There are 4 types, Centrifugal Axial flow Mixed flow Turbine The rotating element is impeller which creates radial flow of water. 4

5. Rotodynamic pump Figure 03: Axial flow pump Figure 04: Mixed flow pump 5

6. Rotodynamic pump,cont …. Figure 05: Radial flow (Centrifugal pumps) 6

7. Pumping theory: Energy is imparted to the water by a unit of rotating vanes called an impeller, which are located in a stationary body called the casing . Water is pushed into the center or eye of the impeller by atmospheric or water pressure. Then it sets into a rotary motion by the impeller. The rotating movement causes a centrifugal force to act upon the water. It drives the water outward, between the vanes of the impeller, into the surrounding casing from where it moves to the pump outlet. 7 Centrifugal pump

8. Casing I mpellers are fitted inside casings. The area of flow of the casing gradually increases in the direction of flow of water. It convert kinematic energy into pressure energy. R educing speed while increasing pressure . S eal it to prevent leakage and sometimes retain pressure. S upport some of the key parts such as shafts, bearings, etc. 8

9. There are 2 types, Volute type Turbine type Casing of radial flow centrifugal pump Figure 06: Volute type Figure 07:Turbine type 9

10. Casing of radial flow centrifugal pump, cont …. Volute type The 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, slowing down the fluid’s rate of flow. According to Bernoulli’s principle , the volute converts kinetic energy into pressure by reducing speed while increasing pressure. Turbine type Impeller surrounded by stationary guide vanes Reduce the velocity of water before entering Creating pressure head 10

11. Impellers Impellers can be classified according to the direction of flow through the impeller in relation to the axis of rotation as, Radial Axial Mixed flow The most efficient impeller is an axial flow one which creates high flows at low heads. 11

12. 12 Impellers, cont … Figure 09: Radial flow Figure 08: Axial flow Figure 10: Mixed flow

13. Impellers can also be classified according to their design into, Open Semi-open Enclosed Open impeller It has the vanes free on both sides Open impellers are structurally weak Use in small-diameter, inexpensive pumps and in pumps handling suspended solids 13 Impellers

14. Semi open impeller The vanes are free on one side and enclosed on the other side. The shroud adds mechanical strength Higher efficiency compare to open impeller Closed impeller The vanes are located between the two discs, all in a single casting. Use in large pumps with high efficiencies and low required Net Positive Suction Head  The centrifugal pumps with closed impeller are the most widely used pumps handling clear liquids. Impellers 14

15. 15 Impellers, cont … Figure 12: Enclosed impeller Figure 13: Semi-open impeller Figure 11: Open impeller

16. Centrifugal pump installation Figure 14: installation of Centrifugal pump 16

17. 17 Pump Jargon

18. Total static head: Vertical distance between the free level of the source of supply and the point of free discharge or the free surface of the discharge liquid . Static Discharge Head Vertical distance from pump centerline to the point of free discharge or the surface of the liquid in the discharge tank 18 Pump Jargon, cont ….

19. 19 Pump Jargon, cont …. Figure 15: Total static head

20. Pump Jargon, cont … ( Total) Static head: Difference in head between suction and discharge sides of pump in the absence of flow; equals difference in elevation of free surfaces of the fluid source and destination Static suction head: Head on suction side of pump in absence of flow, if pressure at that point is >0 Static discharge head: Head on discharge side of pump in absence of flow Total static head Static suction head Static discharge head 20

21. Pump Jargon, cont … (Total) Static head: Difference in head between suction and discharge sides of pump in the absence of flow; equals difference in elevation of free surfaces of the fluid source and destination Static suction lift: Negative head on suction side of pump in absence of flow, if pressure at that point is <0 Static discharge head: Head on discharge side of pump in absence of flow Total static head Static suction lift Static discharge head 21

22. Pump Jargon, cont ….. Total static head (both ) Static suction lift Static discharge head Static suction head Static discharge head Note: Suction and discharge head / lift measured from pump centerline 22

23. Total Dynamic Suction Lift or Head (fluid below suction) Static suction lift - velocity head at suction + total friction head in suction line (fluid above suction) Static suction head + velocity head at pump suction flange – total friction head in suction line Velocity head = energy of liquid due to motion 23 Pump Jargon, cont …..

24. Total Dynamic Discharge Head (TH or TDH ) Same as corresponding static heads But it includes friction losses due to piping and velocity (tank above suction) : Total dynamic discharge head – total dynamic suction head (tank below suction) : Total dynamic discharge head + total dynamic suction lift 24 Pump Jargon, cont ….

25. 25 Pump Jargon, cont …. Figure 16: TDH (tank above suction) Figure 17: TDH (tank below suction)

26. 26 How the centrifugal pump works Figure 18: Working pattern of centrifugal pump

27. The water being discharged from the pump is forced into a manifold. This is the junction for all discharge lines. The manifold has all of the discharge valves that are controlled from the pump panel. 27 Discharge Manifold Figure 19: Discharge manifold

28. Water that is held in closed lines and in the pump will be warmed by the friction of the running pump. If let go long enough, the water can boil and cavitate the pump. 28 The condition when pump running, but not discharging Figure 20: Pump running without discharging

29. Cavitation It occurs when there is too much air in the pump, or there is more water being discharged than that is coming into the pump 29 Figure 21: Pump cavitation

30. Pumps need the water for, Cooling Lubrication Swelling the packing Without water in the pump, the heat from friction will quickly destroy a pump. 30 Running of pump without water Figure 22: Heat generation in pump

31. Advantages Initial and maintenance cost are low Simple mechanism Operated by high speed motor/engine Durable Cheap Simple in construction No metal to metal fits Handle liquid with large amount of solids No valves involved in pump operation Advantages and disadvantages of centrifugal pumps 31

32. Disadvantages Require priming Check valve is required to avoid back flow Discharge varies with head Efficiency is low at high heads Suction is limited Can not handle highly viscous fluids efficiently 32 Advantages and disadvantages of centrifugal pumps, cont …

33. The liquid is displaced / pushed by moving part Mechanically induced vacuum in a chamber draws a volume of water There are 2 types , Reciprocatory pump Rotary type pump Positive displacement pump 33

34. Figure 23: Hand operating reciprocatory pump Figure 24: Deep well reciprocatory pump Reciprocatory pump 34

35. Reciprocating pump consists of a piston moving in a cylinder. This movement, in conjunction with a valve system allows water to be lifted from one level to another. The pump delivers a comparatively low discharge. But pump output is almost the same whatever the working head. 35 Reciprocatory pumps, cont ….

36. Advantages Constant discharge at variable heads Durable & flexible High efficiency is possible Disadvantages Initial and installation cost is high Occupy larger space Not suitable for pumping water that contains sediments Maintenance cost is high Reciprocatory pumps, cont …. 36

37. Diaphragm pumps These are similar to the fuel pumps used on automobiles. A flexible diaphragm is used to create suction and discharge. The diaphragm that acting like piston, can be actuated using a cranking device operated manually. Figure 25: Diaphragm pump 37

38. Rotary motion is used here. Rotary elements are cam or gear that fit closely to the casing Rotary pumps Figure 26: Rotary pump with cam Figure 27: Rotary pump with gear 38

39. Advantages of rotary pump No priming Flow is free from pulsation Efficiency is high Disadvantages Cost is high Not durable Sediments in water are damaging the pumps Rotary pumps, cont …. 39

40. Other types of pumps There are some other kinds of pumps, Air lift pump - used for deep wells (60-80m ) Jet pump - suitable f or small wells Hydraulic pump 40

41. Other types of pumps, cont …. Figure 28:Typical arrangement of air lift pump 41

42. Figure 29: Hydraulic pump Figure 30: Jet pump Other types of pumps, cont …. 42

43. It is different from bore hole pump. It is placed below pump bowel within water level. Submersible pump Figure 31: Submersible pump diagram 43

44. Advantages Larger movement of water discharge Sediment water can be pumped Common compressor unit can be used for different pump Good for deep wells Disadvantages Cost high Low efficiency Flow is not continuous Submersible pump, cont … 44

45. It does not utilize the outside power Use the principle of water hammer pressure Developed when a moving rams of water is suddenly stopped. Hydraulic ram Figure 32: Layout of hydraulic ram 45

46. Advantages Simple to operate Durable Cheap Disadvantages Noise pollution Wastage of water Hydraulic ram, cont …. 46

47. THANK YOU 47