An Introduction to Pumps

1. An Introduction toPumps

2. Pumps • Overview • A pump is a piece of equipment used to transfer a liquid or a gas from a source to a destination. • Upon completion of this section, you will be able to perform the following: • Describe the characteristics of centrifugal pumps. • Describe the characteristics of positive displacement pumps. • Discuss general wear patterns and failure modes. • Discuss pump inspections.

3. MM1401 Pump theories and Differences…….. 28 min

4. Types of Pumps • Pumps are classified as follows: • Centrifugal • Radial Flow • Axial Flow • Positive Displacement • Reciprocating • Rotary

5. Centrifugal Pumps Centrifugal Pumps

6. MM0101 Centrifugal Pump Theories…………….. 38 min

7. Centrifugal Pumps • Centrifugal pumps are the most common type of pump used in industry. • They deliver a broad range of flow rates and discharge pressures without requiring complicated equipment. • Centrifugal pumps offer low initial cost, uniform flow, low maintenance requirements, quiet operation, and adaptability to various prime movers.

8. Centrifugal Pump Operation • Centrifugal pumps convert mechanical energy to kinetic energy to raise the pressure of a fluid in two steps. • In the first step, the centrifugal pump moves the fluid in a circular motion (centrifugal action) using an impeller. • In the second step, the impeller sends the fluid into a volute, and the volute changes the velocity energy of the liquid to pressure.

9. Centrifugal Pump Impeller Operation The centrifugal force of the rotating impeller transfers kinetic energy (velocity) to the liquid.

10. MM0104 Centrifugal Pump Components…..…….. (unknow) min

11. Components of Centrifugal Pump The shaft is connected to and rotated by a driver. Because the impeller is mounted on the shaft, the impeller also rotates. Liquid enters the pump casing into the impeller eye. The liquid moves through the vanes inside the rotating impeller, and the vanes are accelerated by the outward centrifugal force.

12. Radial Flow Centrifugal Pump Radial flow pumps are usually used where large discharge pressure is required. • Pumps with single inlet impellers usually have a specific speed below 4,200 RPM.

13. Axial Flow Centrifugal Pump Axial flow pumps are used in systems that need large volumes of fluid but do not typically produce large discharge pressures. Axial flow pumps usually have a specific speed above 9,000 RPM.

14. MM0105 Centrifugal Pump Application …..……... 15 min

15. Axial Flow Centrifugal Pump Axial flow pumps are used in systems that need large volumes of fluid but do not typically produce large discharge pressures. Axial flow pumps usually have a specific speed above 9,000 RPM.

16. Axial Flow Centrifugal Pump Axial flow pumps are used in systems that need large volumes of fluid but do not typically produce large discharge pressures. Axial flow pumps usually have a specific speed above 9,000 RPM.

17. 15 min Quiz

18. Knowledge Check 1.) The 2 sub categories of Centrifugal pump are: • Magnetic, Radial flow • Radial, electric flow • Radial, Axial flow ( correct, slide# 3..to remove answer later)

19. Knowledge Check 2.) The main component that generate the circular motion is: • Blade • Impeller ( correct, slide# 7..to remove answer later) • scooper

20. Knowledge Check 3.) The Centrifugal force of the rotating impeller transfers _______energy ( velocity ) to the liquid. • mechanical • passive • Kinetic ( correct, slide# 8..to remove answer later)

21. Positive Displacement Pumps Positive Displacement Pumps

22. Positive Displacement Pumps • Positive-displacement pumps move a fixed volume of liquid per unit of time. • Positive-displacement pumps are less common than centrifugal pumps, but are used for special applications. • Positive-displacement pumps are used for service with low flow rates, services with high differential pressures, or for liquids that have high viscosities. • The piston converts the mechanical energy into fluid movement. It pushes the fluid out of the pump and draws fluid into the pump as it reciprocates back and forth.

23. Reciprocating Positive Displacement Pump • The cylinder is the tubular chamber that contains the piston. • The piston ring acts as the sealing element between the piston and the cylinder walls. • The check valves control the intake and discharge of fluid from the pump. • The intake valve opens on the intake stoke, allowing fluid into the cylinder.

24. Reciprocating Positive Displacement Pump The discharge valve opens on the discharge stroke. The crankshaft converts circular motion into linear motion. The piston rod transfers the energy form the drive mechanism to the piston. The packing surrounds the rod at the point at which it enters the cylinder and prevents liquid leakage.

25. Reciprocating Positive Displacement Pump The piston starts at the valve end and moves back on the suction stroke to create a suction in the valve end of the cylinder.

26. Reciprocating Positive Displacement Pump • Operating principles apply to all reciprocating pumps, regardless of how many cylinders, pistons and valves are added. • For example Figure 210 shows a double acting pump that pumps fluid on both the forward and reverse piston strokes by the addition of valves and manifolds.

27. Rotary Positive Displacement Pump • Rotary pumps operate on the principle that a rotating vane, screw, or gear traps the liquid in the suction side of the pump casing and forces it to the discharge side of the casing. • Two types of rotary positive displacement pumps: • Gear • Screw

28. Gear-Type Rotary Pump As the gears revolve and the teeth disengage, the space again opens on the suction side of the pump trapping new quantities of liquid and carrying it around the pump case to the discharge. As liquid is carried away from the suction side, a lower pressure is created, which draws liquid in through the suction line.

29. Screw-Type Rotary Pump Liquid is trapped at the outer end of each pair of screws. • As the first space between the screw threads rotates away from the opposite screw, a one-turn, spiral-shaped quantity of liquid is enclosed when the end of the screw again meshes with the opposite screw. • As the screw continues to rotate, the entrapped spiral turns of liquid slide along the cylinder toward the center discharge space while the next slug is being entrapped.

30. MM1404 Positive DisplacementPump Applications ….. 15 min CY0101 Sump Pump Function.……………………….... 9 min

31. CY0101 Sump Pump Function.……………………….... 9 min

32. Wear, Failure, and Inspection For Centrifugal and Positive Displacement Pump: • How they usually wear • How they usually fail • Common inspection methods

33. How Centrifugal Pumps Typically Wear A pump’s shaft will wear where the packing contacts it.

34. How Centrifugal Pumps Typically Wear Bearing housings in a bank of pumps frequently have leaking fluid pouring over the housing. Throat bushings, which form the bottom of the stuffing box, wear if the bearings are excessively worn thus allowing contact between the shaft and bushing.

35. How Centrifugal Pumps Typically Wear Mechanical seals tend to fail instead of wear.

36. How Centrifugal Pumps Typically Wear Impellers generally will not wear if the correct conditions exist within the pump. • An impeller can however erode away to the point that pump performance is severely limited if the pump is run consistently under cavitation.

37. How Centrifugal Pumps Typically Fail • There are several modes of failure including the following: • Shaft • Impeller • Packing or mechanical seals • Other failure modes including misalignment

38. Inspecting Centrifugal Pumps • Visually inspect the pump for loose or missing fasteners on: • Pump casing • Foundation • Motor • Coupling guard • Visually inspect for leakage, pumped fluid or lubrication at: • Pump fittings and piping • Machined sealing joints of pump • Shaft sealing area, if applicable (Packing or mechanical seal) • Check lubrication level, where applicable. • Listen for abnormal noise such as: • Growling or howling • Chattering, Rattling • Use electronic stethoscope

39. Inspecting Centrifugal Pumps • Check for abnormal operating temperatures: • By feel (Note that this is not an accurate method and can be dangerous.) • By contact type thermometer or pyrometer • By local thermometer or temperature indicator • By remote instrumentation, if installed • Check for high vibration: • By feel • By hand-held vibration meter • By remote instrumentation, if installed • Check operating parameters where possible: • Discharge flow • Discharge pressure • Suction pressure • Discharge temperature • Motor current • Rotating speed

40. How Positive Displacement Pumps Typically Wear The most common reason for wear in a positive displacement pump is impurities in the fluid being pumped.

41. How Positive Displacement Pumps Typically Fail • Positive displacement pump failures can come from physical abrasion between moving parts of the pump (e.g. caused by misalignment, bearing wear, etc.) • Loose parts have also caused failure for many pumps. • Pump life is a function of environment. (2 mos.-30 yrs.) • Proper alignment, lubrication, maintenance and operation can keep some pumps running indefinitely.

42. Inspecting Positive Displacement Pumps • Visually inspect the pump for loose or missing fasteners on: • Pump casing • Foundation • Motor • Coupling guard • Visually inspect for leakage, pumped fluid or lubrication at: • Pump fittings and piping • Machined sealing joints of pump • Shaft sealing area, if applicable (Packing or mechanical seal) • Check lubrication level, where applicable. • Listen for abnormal noise such as: • Growling or howling • Chattering • Rattling • Use electronic stethoscope

43. Inspecting Positive Displacement Pumps • Check for abnormal operating temperatures: • By feel (Note that this is not an accurate method and can be dangerous.) • By contact type thermometer or pyrometer • By local thermometer or temperature indicator • By remote instrumentation, if installed • Check for high vibration: • By feel • By hand-held vibration meter • By remote instrumentation, if installed • Check operating parameters where possible: • Discharge flow • Discharge pressure • Suction pressure • Discharge temperature • Motor current • Rotating speed

44. 15 min Quiz

45. Knowledge Check 1.) The key feature of Positive-displacement pump is moving type of liquid with high________. • Clorine level • Opacities • viscosities( correct, slide# 21..to remove answer later)

46. Knowledge Check 2.) The Reciprocating Positive Displacement Pump move fluide on both the forward and reverse piston strokes True ( correct, slide# 25..to remove answer later) False

47. Knowledge Check 3.) The Centrifugal pump typically may fail in one of these mode: • shaft • impeller • Misalignment • All of above ( correct, slide# 36..to remove answer later)