Basics of pumps

Basics of Pumps

1. Basics of Pumps Tahseen Qamhieh Sr. Mechanical Engineer

2. What is Pump? Pumps Common Components Pumps Performance Pumps Classification Dynamic Pumps Centrifugal Pumps Pumps Curves Positive Displacement Pumps Reciprocating Pumps Rotary Pumps Pumps Inspection Page 2 Presentation Outline

3. A pump is a device which moves fluids by mechanical action from one place to another. BASICS OF PUMPS Page 3 What is Pump?

4. Pumps Common Components

5. Inlet – where liquid enters the pump. This side of the pump is also called the suction side. Outlet – where liquid leaves the pump. The pressure of the liquid is highest at this point. Casing – This part is to contain the liquid inside the pump during operation. It houses all of the pump internal parts. BASICS OF PUMPS Page 5 Pump Major Components

6. Shaft – used to transfer power from driver to component that moves liquid Driver – supply the power needed to produce the pumping action Coupling – a device that connect the drive shaft to the pump shaft Strainers – a device used to trap & remove solids before they enter the pump Lubricating System – to lubricate pumps bearings Bearings – used to support and align moving parts of pump BASICS OF PUMPS Page 6 Pump Auxiliary Equipment's

7. BASICS OF PUMPS Page 7 Pump Common Components

8. Passive Feed Systems: Use delivery methods such as gravity to deliver lubricants to the bearings. Forced Feed Systems: When pumps need a greater supply of lubricant to the bearings. BASICS OF PUMPS Page 8 Types of Lubricating System

9. Pumps Performance

10. Flow Rate = Pump Capacity Flow Rate expressed as gallons/minute BASICS OF PUMPS Page 10 Pump Flow Rate Definition

11. A measurement of pressure. Weight of column liquid. Head expressed in Feet or Meter Example: 25 feet water level = 25 feet of head at base BASICS OF PUMPS Page 11 Pumps Head Definition

12. Static Head – measured from inlet centerline to liquid level. Suction Head – measured at pump inlet. Discharge Head – measured at pump outlet (Head related to pressure) Dynamic Head – caused by moving liquid. Total Head – produced inside the pump. BASICS OF PUMPS Page 12 Head Types

13. Pumps Classification

14. BASICS OF PUMPS Page 14 Pumps Dynamic Positive Displacement Specialty Pumps Axial Flow Mixed Flow Radial Flow Reciprocating Rotary Piston/Plunger Diaphragm Bladder Axial Radial Mech. Drive Hydro. Drive Air Drive Gear Lobe Screw Cavity Vane Peristaltic Ext. Low Press. High Press. Solen . Drive Int. Centrifugal

15. Dynamic Pumps

16. Energy is added to the fluid continuously through the rotary motion of the blades. This increase in energy is converted to a gain in pressure energy when the liquid is allowed to pass through an increased area. BASICS OF PUMPS Page 16 Principle of Operation Recommended media (fluid): water and relatively thin liquids. Not recommended for thicker oils.

17. Centrifugal Pumps

18. The most common type of pump used in industry due to its simple working principle and relatively inexpensive manufacturing cost. BASICS OF PUMPS Page 18 Centrifugal Pump Principle Works on the principle of centrifugal force by pushing the liquid away from the center in tangential direction. Operate using kinetic energy to move fluid utilizing an impeller & a circular pump casing. The impeller produces liquid velocity & the casing forces the liquid to discharge from the pump converting velocity to pressure.

19. Shaft – transmit the torque/power and supporting the impeller & other rotating parts. Impeller – transmit energy into the fluid (hydraulic energy). An impeller has vanes that pushes the liquid. Casing – where the impeller is fitted. Bearings – keep the shaft in correct alignment with the stationary parts. BASICS OF PUMPS Page 19 Major Parts of Centrifugal Pump

20. Liquid forced into impeller. Vanes pass kinetic energy to liquid. Liquid rotates and leaves impeller. Volute casing converts kinetic energy into pressure energy. BASICS OF PUMPS Page 20 How it Works?

21. Open – no shrouds or wall to enclose the vanes. Semi open – shrouds or sidewall partially enclosing the vanes. Closed – shrouds or sidewall enclosing the vanes. BASICS OF PUMPS Page 21 Types of Impeller

22. Volute Casing Vortex Casing Diffuser Ring Casing BASICS OF PUMPS Page 22 Construction of the Pump Casing

23. Single Stage Pump – has just one impeller and is better for low head service. Two Stage Pump – has two impellers mounted in series for medium head service. Multistage Pump – has three or more impellers mounted in series for high head service. BASICS OF PUMPS Page 23 Pumps Classification According to Number of Impellers

24. Horizontal Shaft Pump Vertical Shaft Pump BASICS OF PUMPS Page 24 Pumps Classification According to position of Shaft

25. Radial Flow Pumps – high Pressure, low flow pumps which accelerate fluid along the impeller blades perpendicular to the shaft. Mixed Flow Pumps – medium flow, medium pressure pumps which push fluid out away from the pump shaft at an angle greater than 90°. Axial Flow Pumps – high flow, low pressure pumps which lift fluid in a direction parallel to the impeller shaft. BASICS OF PUMPS Page 25 Pumps Classification According to the Direction of Flow

26. Long-coupled pump: pump connected to the motor by means of a flexible coupling. The motor and the pump have separate bearing constructions Close-coupled pump: pump connected to the motor by means of a rigid coupling. BASICS OF PUMPS Page 26 Long-coupled and Close-coupled Pumps

27. BASICS OF PUMPS Page 27 End-Suction Pump Horizontal Multistage Close-coupled Long-coupled Single Stage Close-coupled → The liquid runs directly into the impeller. Inlet & outlet have a 90° angle

28. BASICS OF PUMPS Page 28 In-line Pump Horizontal Multistage Close-coupled Long-coupled Single Stage Close-coupled → The liquid runs directly through the pump in-line. The suction pipe and the discharge pipe are placed opposite one another and can be mounted directly in the piping system Vertical Single Stage Long-coupled

29. Pumps Curves

30. Curve graphs represent design characteristics. The performance of a centrifugal pump is shown by a set of performance curves. The performance curves for a typical centrifugal pump shown on the figure as a function of the flow; Head, Power consumption, Efficiency and NPSH. BASICS OF PUMPS Page 30 Pump Curves

31. The QH-Curve shows the head, which the pump is able to perform at a given flow. BASICS OF PUMPS Page 31 Head, the QH-Curve

32. The efficiency ƞ P is the relation between the power, which the pump delivers to the water (P H ) & the power input to the shaft (P ₂) ƞ P = P H / P ₂ = ( ρ . g . Q . H) / ( P ₂ x 3600) Where: ρ is the density of the liquid in kg/m³ g is the acceleration of gravity in m/s² Q is the flow in m³/h H is the head in m BASICS OF PUMPS Page 32 Efficiency, the ƞ-Curve

33. For water at 20°C & with Q measured in m³/ hr and H in m, the hydraulic power can be calculated as: P H = 2.72 . Q . H [W] BASICS OF PUMPS Page 33 Efficiency, the ƞ-Curve The efficiency depends on the duty point of the pump. Therefore it is important to select a pump, which fits the flow requirements and ensures that the pump is working in the most efficient flow area. Maximum efficiency point = Provides most flow for least amount of power.

34. The P ₂-Curve of most centrifugal pump is similar to the one shown on the figure, where the P₂ value increases when the flow increases. P₂ = (Q . H . g . Ρ ) / (3600 x ƞ P ) BASICS OF PUMPS Page 34 Power Consumption, the P ₂-Curve

35. The NPSH-value of a pump is the minimum absolute pressure that has to be present at the suction side of the pump to avoid cavitation . The NPSH-value is measured in (m) and depends on the flow; when the flow increases, the NPSH-value increases as well. BASICS OF PUMPS Page 35 NPSH-Curve (Net Positive Suction Head)

36. NPSHA combines the effect of atmospheric pressure, water temperature, supply elevation and the dynamics of the suction piping. NPSHA = Ha +/- Hz – Hf + Hv – Hvp Ha: the atmospheric or absolute pressure. Hz: the vertical distance from the surface of the water to the pump centreline. Hf: the friction formed in the suction piping. Hv : the velocity head at the pump's suction. Hvp : the vapor pressure of the water at its ambient temperature. BASICS OF PUMPS Page 36 NPSH A (Net Positive Suction Head Available)

37. Cavitation: Is defined as formation and collapse of vapor bubbles. Caused by low suction head. Means when suction head drop below its design value. Higher temperatures increase chance of cavitation Cavitation wears away pump components BASICS OF PUMPS Page 37 Suction Head and Cavitation

38. Pumps connected in Parallel: Pumps connected in parallel are often used when: The required flow is higher than what one single pump can supply. The system has variable flow requirements and when these requirements are met by switching the parallel connected pumps ON and OFF. Normally, pumps connected in parallel are of similar type and size. Q = Q ₁ + Q ₂ H = H₁ = H₂ BASICS OF PUMPS Page 38 Pumps Coupling of Stages

39. Pumps connected in Series: Normally, pumps connected in series are used in systems where a high pressure is required. Q = Q ₁ = Q ₂ H = H₁ + H₂ BASICS OF PUMPS Page 39 Pumps Coupling of Stages

40. Positive Displacement Pumps

41. Include all pumps which use fixed volume cavities displaced using a mechanical force to move fluid through the system. BASICS OF PUMPS Page 41 Positive Displacement Pumps Positive Displacement Pumps Classification: Reciprocating Pumps Rotary Pumps

42. Reciprocating Pumps

43. Use linear rather than rotary motion to move fluids. BASICS OF PUMPS Page 43 Reciprocating Pump Principle Utilize a piston or diaphragm which draws fluid in (upstroke) and pushes it out ( downstroke ), using check valves to regulate and direct flow through the system. It is often used where a relatively small quantity of liquid is to be handled and where delivery pressure is quite large.

44. Pumps that use a plunger or piston to move media through a cylindrical chamber. The pressure in the chamber actuates the valves at both the suction and discharge points. BASICS OF PUMPS Page 44 Piston/Plunger Pumps

45. Single Acting – pumps have one valve on each end, where suction and discharge take place in opposite directions. Double Acting – pumps utilize two valves on each end, allowing suction and discharge in both directions. BASICS OF PUMPS Page 45 Pump Action

46. Simplex – pumps have one cylinder Duplex – pumps have two cylinders Multiplex– pumps have more than two cylinders BASICS OF PUMPS Page 46 Number of Cylinders

47. Axial – Contain a number of pistons attached to a cylindrical block which move in the same direction as the blocks centerline (axially) BASICS OF PUMPS Page 47 Axial Vs. Radial Radial – Contain pistons arranged like wheel spokes around a cylindrical block. A drive shaft rotates this cylindrical block which pushes or slings the pistons.

48. Low flow pneumatic devices used mainly for fluid sampling applications. Consist of a flexible squeezable bladder encased in a rigid outer casing. Utilize hydrostatic pressure to draw water into the bladder and pass it through a check valve at the bottom of the pump. When the bladder is full, the check valve closes to prevent backflow, and the water is pumped up to the surface via injected gas pressure which squeeze the bladder. BASICS OF PUMPS Page 48 Bladder Pumps

49. Work by flexing the diaphragm out of the displacement chamber. When the diaphragm moves out, the volume of the pump chamber increases and causes the pressure within the chamber to decrease and draw in fluid. The inward stroke has the opposite effect decreasing the volume and increasing the pressure of the chamber to move out fluid. Recommended media (fluid): wide range of liquids, including liquids containing solids and corrosive liquids. BASICS OF PUMPS Page 49 Diaphragm Pumps

50. Mechanical – operated using a simple & robust reciprocating mechanical linkage directly attached to the diaphragm. BASICS OF PUMPS Page 50 Diaphragm Pumps Drive Mechanism Hydraulic – Implement an intermediate hydraulic fluid on the opposing side of the diaphragm.

51. Solenoid – have an electric motor that controls a solenoid magnet. BASICS OF PUMPS Page 51 Diaphragm Pumps Drive Mechanism Air – pumps which use compressed air to drive diaphragms.

52. Single Acting – pumps incorporate one diaphragm and one set of valves. Double Acting – pumps incorporate two diaphragms and two sets of valves. BASICS OF PUMPS Page 52 Diaphragm Pump Action

53. Rotary Pumps

54. Move fluid using rotating mechanical motion. As the rotor of the pump spins in a circular motion, liquid is drawn into and forced out of spaces created by the moving parts. BASICS OF PUMPS Page 54 Rotary Pump Principle

55. The most common type of positive displacement pump used. Typically, a rotating assembly of two gears (a drive gear and an idler) moves to create suction at the pump inlet and draw in fluid. The liquid is then directed between the teeth of the gears and the walls of the casing to the discharge point. Volume decreases as the liquid travels from inlet to outlet, causing a buildup of pressure. Recommended media (fluid): oils and other high viscosity liquids. BASICS OF PUMPS Page 55 Gear Pumps

56. Utilize two identical gears with external teeth to generate flow. The rotation of the gears is such that the liquid comes into the inlet port and flows into and around the outer periphery of the two rotating gears. As the liquid comes around the periphery it is discharged to the outlet port. BASICS OF PUMPS Page 56 External Gear Pumps

57. Generate flow using a gear with externally cut teeth contained in and meshed with a gear with internally cut teeth. As the gears come out of mesh on the inlet side, liquid is drawn into the pump. The liquid is forced out the discharge port by the meshing of the gears. BASICS OF PUMPS Page 57 Internal Gear Pumps

58. Similar to gear pumps in terms of operation in that fluid flows around the interior of the casing. Multiple lobes on the rotating elements provide the ability to drive large solids & slurry-laden media. Typically, they are available in double-lobe or triple-lobe configuration. Recommended media (fluid): liquids which are viscous or which contain fragile solids or are shear sensitive. BASICS OF PUMPS Page 58 Lobe Pumps

59. Use one or more screws to transfer fluids along an axis. The pumping liquid from the inlet is trapped between the teeth of the idler screws. Though continuous, the flow can be considered as a series of packets lying between a set of two adjacent threads of the idler. The rotation of the driver causes each packet of trapped liquid to move progressively forward in the axial direction & ultimately to the outlet. Recommended media (fluid): oils, fuels and other high viscosity liquids. Also handle two-phase liquid/gas mixtures. BASICS OF PUMPS Page 59 Screw Pumps

60. Use rotating mechanisms to push fluids through continuously moving open cavities. Recommended media (fluid): wide variety of thin and thick liquids, including corrosive liquids and liquids containing solids. BASICS OF PUMPS Page 60 Progressive Cavity Pumps

61. Pumps create regions of low pressure by moving fluid using a rotating vane assembly in the pumping chamber. Typically there are two or more rotating vanes that move the fluid from inlet to outlet. Recommended media (fluid): oils & other high viscosity liquids. Also good for thin liquids like gasoline and water. BASICS OF PUMPS Page 61 Vane Pumps

62. Consist of a tube which is squeezed by a set of rollers or shoes to move fluid. By constricting the tube and increasing the low pressure volume, a vacuum is created to pull the liquid into the tube. Once in the pump, the liquid is pushed through by compressing the tube at a number of points in contact with the rollers or shoes. The media is moved through the tube with each rotating or oscillating motion. Recommended media (fluid): wide range of liquids, including liquids containing solids and corrosive liquids. BASICS OF PUMPS Page 62 Peristaltic Pumps

63. Low Pressure – laboratory grade pumps designed for low pressure pumping applications. High Pressure – industrial grade pumps designed for high pressure pumping applications. BASICS OF PUMPS Page 63 Peristaltic Pumps

64. Pumps Inspection

65. Improper Pressure or Flow: Pump – F oreign matter in pump, W orn or damaged pump ports, R elief valve improperly seated, C avitation, Air trapped in pump. Suction Line – I nsufficient supply of liquid, C logged suction line, S uction valve in wrong position, E xcessive amount of air or gas in liquid, I nadequate suction head, I mproper liquid viscosity, C logged strainer. Discharge Line – D ischarge valve in wrong position, C logged discharge pipe. BASICS OF PUMPS Page 65 Symptoms of Pump Problems

66. Overheating: Pump – C avitation, A ir or vapor trapped in pump, I mproperly installed packing. Bearings – I nsufficient or improper lubrication, I nsufficient cooling of lubricant, D amaged bearings. Coupling – M isalignment of driver and pump shafts, W orn or defective coupling. BASICS OF PUMPS Page 66 Symptoms of Pump Problems

67. Sounds (Excessive Noise or Unusual Vibration): Pump – A ir or vapor trapped in pump casing, C avitation, Foreign matter in pump, W orn or damaged parts, R ubbing of rotating and stationary parts, B ent shaft. Suction Line – I nsufficient liquid supply, I nadequate suction head. Bearing – B earing damage, I nadequate or improper lubrication. Coupling – M isalignment of driver and pump shafts, W orn of defective coupling. Motor Base – M alfunctioning driver, D river or pump foundations not rigid. BASICS OF PUMPS Page 67 Symptoms of Pump Problems

68. Check: Suction piping Suction valve packing and gasket Pump Packing Mechanical seals Pump bearings Discharge piping BASICS OF PUMPS Page 68 Checking for Leaks

69. Signs of Cavitation: Rattling noise, like marbles Discharge pressure fluctuations Overheated pump casing Decrease in flow BASICS OF PUMPS Page 69 Checking for Cavitation

70. Stopping or Minimizing Cavitation: Raise suction head above MNPSH. If permitted, increase pressure in pump by temporarily restricting discharge. Lower process fluid temperature (if permitted) BASICS OF PUMPS Page 70 Checking for Cavitation

71. Thank You