18. Positive Displacement Pumps

19. Centrifugal Pumps

20. Centrifugal Pumps 8 9 1.Casing, volute
2. Impeller, vanes, vane tips, backplate, frontplate (shroud), back vanes, pressure equalising passages
3. Back cover parallel to Plane of the impeller intake
4. Stuffing Box - Gland/mechanical seal housing, packing/lantern ring
5. Pump shaft
6. Pump casing
7. Bearing housing
8. Bearings
9. Bearing seals 8 9

21. Centrifugal Pumps

23. Parts of a Pump Prime Mover - drives the pump
Steam
Electric motor
Gear driven from an engine
Human
Shaft - connects the pump to prime mover
Pump Mechanism - converts the energy provided by the prime mover the flow energy

24. Pump Curve for a Positive Displacement Pump

25. Simple Positive Displacement Pump

26. Reciprocating Piston
Uses a plunger and cylinder design to deliver constant volume of fluid with each stroke.
Used in bilge, steering, and emergency feed pumps

27. Gear
Uses gears to deliver a constant volume of fluid with little pressure fluctuation.
Used in control oil and lubricating pumps

28. Rotary Screw
Similar to a gear pump but it operates at a much larger capacity.

29. Centrifugal Pumps
Pumps designed to deliver various flows based on system discharge pressure
Centrifugal pump laws
flow is proportional to the speed
Pressure (head) is proportional to speed2
Power is proportional to speed3

30. Pump Curve for a Centrifugal Pump

31. Fluid is drawn into the suction due to a low pressure created as the impeller rotates. The vanes impart momentum upon the fluid. Since the flow rate through the pump is constant, the flow increases due to the increase in cross-sectional area of the vanes. The volute converts the kinetic energy to flow energy as seen in an increase in pressure.

32. Centrifugal Pump Placement
Series - this will increase the pump pressure, but the flow will remain constant.
Used to meet NPSH requirements
Parallel - this will increase the flow, but the pressure will remain the same.
-Used in condesate systems

33. Jet Pumps They work on the venturi effect
Used in air ejectors and eductors