This document discusses key principles of hydraulic and pneumatic systems including: - Pascal's law which states that pressure in a fluid is transmitted equally in all directions - Energy transfer from a prime mover like a pump to an actuator - The role of fluid flow in operating actuators by extending or retracting cylinders - How actuator speed is determined by flow rate and cylinder volume displacement - How pressure results from restricting fluid flow from a pump - The use of schematics using standardized symbols to represent hydraulic and pneumatic components.

1. Hydraulic and Pneumatic
actuators

2. Fluid Power Principles
Pascal’s Law
Relationship between force, pressure, and area
force =pressure area
force
pressure =
area
force
area =
pressure


3. Fluid Power Principles
Pascal’s Law
Pressure applied on a confined fluid at rest is
transmitted undiminished in all directions and acts with
equal force on equal areas and at right angles to them.
Since the pressure is the same on both sides,
we see that P = F1/A1 = F2/A2. Therefore, the
force F2 is larger than F1 by multiplying factor
A2/A1. Hydraulic brakes, car lifts, hydraulic
jacks, and forklifts all make use of this
principle.

4. Fluid Power Physics
Energy
The ability to do work
Energy Transfer
From prime mover, or input source, to an actuator, or
output device

5. Fluid Power Principles
Flow
Makes actuator operation possible
To extend the cylinder, flow must be directed into
port B.
Retracted cylinder

6. Fluid Power Principles
Flow
Makes actuator operation possible
Flow is directed into Port B
and cylinder is extended.
To retract the cylinder, flow must be directed into
what port?

7. Fluid Power Principles
Flow
Makes actuator operation possible
To retract the cylinder, flow must be directed into
what port?
The cylinder retracts when
flow is directed into Port A.

8. Fluid Power Principles
Rate of Flow
Determines actuator speed
Measured in gallons per minute (gpm)
Generated by a pump

9. Fluid Power Principles
With a Given Flow Rate
Actuator volume displacement directly
affects actuator speed
The less volume to displace, the faster the
actuator
Will the actuator illustrated below travel the same
speed as it retracts and extends if a constant flow rate
is maintained? No. The actuator will travel faster as it
retracts due to less volume caused by the
actuator shaft.

10. Fluid Power Principles
Pressure
The resistance to flow
Pumps produce flow, not pressure
- If you restrict the flow from the pump, pressure will result.
All points of resistance in series within a system
contribute to total system pressure, including long runs
of pipe, elbows, etc.

11. Fluid Power Schematics
Schematics
Line drawing made up of a series of symbols and connections that
represent the actual components in a hydraulic system

12. Fluid Power Schematics
Symbols
Critical for technical communication
Not language-dependent
Emphasize function and methods of operation
Basic Symbols

13. Fluid Power Schematics
Lines

14. Fluid Power Schematics
Reservoirs

15. Fluid Power Schematics
Pumps

17. (a) Gear pump, (b) vane pump, (c) radial piston pump, (d) axial piston pump with swash plate

18. (a) Single-acting, single stage, vertical, reciprocating
compressor, (b) rotary vane compressor, (c) screw compressor

20. Directional Control Valves
Fluid Power Schematics

21. Pressure Relief Valve

23. Fluid Power Schematics
Check Valves

24. 2/2 Directional control valve
Ports/Positions

25. 3/2 Directional control valve

26. 4/2 Directional control valve

27. 4/3 Directional flow control valve

30. 4/3 Direction Control Valve

34. 3/2 Pushbutton valve with a single acting actuator.

35. 3/2 Pushbutton valve with a single acting
actuator and flow control valve.

36. 3/2 pushbutton valve, a 5/2 Pilot controlled pneumatic
valve and a double acting actuator.

37. 3/2 pushbutton valve, a 5/2 Pilot controlled pneumatic valve and two flow control valves.

39. Assignment
• Design a Circuit for sequencing two cylinders for pick and place
operations
• Deign a Pneumatic operated robotic manipulator for Adjusting a tool
attached to a spindle.