basics of hydraulics

1. Unit 1
Basics of Hydraulics

5. Viscometer

7. AUTOMOTIVE SHOCK ABSORBERS: VISCOSITY AT
WORK
Oil in Lower Chamber
Gas in Upper Chamber
Floating piston between gas and oil

10. Check the Pascal’s law
For the fluid power automotive
lift system, the hydraulic piston
has a 250-mm diameter. How
much oil pressure (kPa) is
required to lift a 13,300-N
automobile?

13. The Siphon

14. Frictional Losses
Types of flows
Friction factor
Head loss
Energy losses
Energy analysis of a complete hydraulic circuit.
More tortuous the path, the greater the losses

16. DARCY’S EQUATION

17. Effect of Pipe Roughness

18. Moody Diagram

19. LOSSES IN VALVES AND FITTINGS
The K Factor
Energy losses in valves and fittings such as tees, elbows, and bends
Common Valves and Fittings

20. Ref: Esposito

21. Hydraulic Circuit

22. The pump is adding 3.73 kW to the fluid.
Pump flow is 0.00190 m3/s.
The pipe has a 0.0254-m inside diameter.
The specific gravity of oil is 0.9.
The kinematic viscosity of oil is 100 cS.
The elevation difference between stations 1 and 2 is 6.10 m.
Pipe lengths are as follows: pump inlet pipe length = 1.53 m and pump outlet pipe
length up to hydraulic motor = 4.88 m

23. Non Positive displacement Pump
Dynamic (non positive displacement) pumps. This type is generally used for low-
pressure, high-volume flow applications.
maximum pressure capacity is limited to 250–300 psi.
centrifugal and the axial flow propeller pumps

24. Positive displacement pumps
a. High-pressure capability (up to 12,000 psi)
b. Small, compact size
c. High volumetric efficiency
d. Small changes in efficiency throughout the design pressure range e. Great
flexibility of performance (can operate over a wide range of pressure requirements
and speed ranges)
Types gear, vane, and piston

27. 1. Gear pumps (fixed displacement only by geometrical necessity)
a. External gear pumps
b. Internal gear pumps
c. Lobe pumps
d. Screw pumps
2. Vane pumps
a. Unbalanced vane pumps (fixed or variable displacement)
b. Balanced vane pumps (fixed displacement only)
3. Piston pumps (fixed or variable displacement)
a. Axial design
b. Radial design

28. External Gear Pump

29. Internal Gear Pump

30. Gerotor Pump

31. Lobe Pump

32. Screw Pump

33. VANE PUMPS

34. Variable Displacement Pump

35. Balanced Vane Pump

36. Axial Piston Pump

38. In-Line Piston Pump

39. Radial Piston Pump

41. Swash Plate

42. Pump Comparison
Ext Gear Int Gear Gerotor Screw Vane Axial Swash Radial
Pressure < 200 psi 500-2500
psi