ELT 792 - Hydraulics & Pneumatics Lab

1. Operate and troubleshoot hydraulic and pneumatic circuits. PERFORM THE FOLLOWING TASKS FOR EACH OF THE LAB EXPERIMENTS AS INSTRUCTED
   1. Observe and practice safety precautions
   2. Interpret a given circuit plumbing diagram
   3. Draw a schematic diagram when given the plumbing diagram using standard American National Standards Institute (ANSI) symbols
   4. Connect the circuit using either the plumbing diagram or the schematic diagram
   5. Make settings and adjustments
   6. Record settings and measurements
   7. Analyze and evaluate circuits and recorded data
   8. Calculate circuit parameters
   9. Compare and list similarities/differences between circuits
   10. Predict results/outcomes when circuit variables are changed
   11. Complete check-out activities at the end of each lab exercise
2. Set maximum pump pressure to safely limit system pressure
3. Operate hydraulic components within manufacturer’s specified limits
4. Identify a pump which is experiencing cavitation (true cavitation
   1. Demonstrate true pump cavitation
   2. Recognize sounds associated with true cavitation
   3. List causes and effects of true cavitation
5. Identify a pump which is experiencing pseudo-cavitation
   1. Demonstrate pseudo-cavitation
   2. Recognize sounds associated with pseudo-cavitation
   3. List causes and effects of pseudo-cavitation
6. Measure pump flow rate
7. Describe how to test a new or rebuilt pump
8. Control cylinder position and movement
9. Observe how valve spool variations effect double acting cylinder behavior in different applications
10. Verify that cylinder entering and discharge flow rates are not the same
11. Determine the size of system components
12. Use hydraulic cylinders which employ cushions
    1. Explain why cylinder cushions are used
    2. Observe how cylinder cushions function
    3. Describe cushion limitations
    4. Perform cushion adjustments
13. Use a 2:1 cylinder to increase rod velocity when approaching the work load
    1. Show how a cylinder of the correct proportion (rod to bore) can be used to obtain a rod speed twice the normal speed that pump flow alone would normally dictate
    2. Describe how cylinder regeneration works
    3. Illustrate how to automatically take a cylinder out of regeneration when it contacts the work load
14. Operate a hydraulic circuit employing meter-in speed control
    1. Observe how Meter-In speed control effects all of the components in the interacting hydraulic circuit
    2. Explain why and when Meter-In control is used
    3. Determine repeatability for a given pressure setting
15. Summarize the effects of system pressure variations and work load variations in determining actuator speed for hydraulic circuits employing ‘non-compensated’ flow control valves
    1. Determine how flow varies with pressure change using a non­compensated needle valve
    2. Observe cylinder action during cylinder extension and retraction
    3. Observe how a needle valve combined with a reverse free flow check valve effects cylinder operation in both Meter-In and Meter-Out modes
    4. Verify that non-compensated flow control valves are good metering devices as long as pressure differential across the valve remains relatively constant
16. Summarize the effects of system pressure variations and work load variations in determining actuator speed for hydraulic circuits employing ‘pressure compensated’ flow control valves
    1. Demonstrate the conditions under which a pressure compensated flow control valve is effective
    2. Describe the limitations of a P.C.F.C. valve in controlling actuator speed
17. Compare the action of Meter-Out with Meter-In flow control using the pressure compensated type flow control valve
    1. Determine the effectiveness of the P.C.F.C. valve in Meter-Out mode with sudden changes in work load resistance
    2. Observe that cylinder rod end pressure intensification can occur with Meter-Out flow control unless proper precautions are taken
18. Compare bleed-off flow control with series flow control as they effect circuit operation
    1. Analyze a hydraulic circuit which employs a pressure compensated flow control valve in a bleed-off circuit configuration
    2. Determine how and when to use Bleed-Off flow/speed control
19. Compare 3-port with 2-port pressure compensated flow control valves
    1. Observe how a bypass (3-port) flow control valve functions
    2. Determine the applications which use a bypass flow control valve
    3. Determine 3-port flow control valve limitations
20. Use Accumulators in hydraulic circuits
    1. List safety precautions associated with accumulators and accumulator circuits
    2. Determine how accumulators interact with other circuit components
    3. Identify the limitations of accumulator circuits
21. Use pilot operated check valves in hydraulic circuits
    1. List the safety precautions associated with P.O.C.V.s.
    2. Observe P.O.C.V. action in a hydraulic circuit
    3. Identify proper applications and limitations of P.O.C.V.s
    4. Describe variations of P.O.C.V.s for special applications
22. Operate hydraulic motors connected for Meter-In configurations
    1. Identify applications and limitations of Meter-In circuits
    2. Discuss malfunctions and troubleshooting related to hydraulic motors
    3. Observe operation for constant and variable loads
23. Compare circuit operation when hydraulic motors are connected for Meter-Out vs. Meter-In configurations
    1. Operate hydraulic motors connected for Meter-Out configurations
    2. Determine if more accurate speed control can be obtained with Meter-Out flow control
    3. Gather data on non-pressure and pressure compensated flow control Meter-Out performance
24. Use Brake Valves to stop hydraulic motors
    1. Observe how the hydraulic actuated brake valve is applied to a hydraulic motor circuit
    2. Observe the interaction between components
25. Use Cross-Over Relief Valves to stop hydraulic motors.
    1. Operate and adjust the Cross-Over Relief valve for various circuit conditions
    2. Observe cross-over relief valve behavior and limitations
26. Summarize applications, advantages, and disadvantages of compressed air
27. Outline safety practices associated with compressed air operations
    1. Describe 13 safety rules necessary to use compressed air or gas
    2. List devices or methods used to safely apply compressed air or gas
28. Use pneumatic symbols in pneumatic circuit schematic drawings
    1. Identify and group the symbols used for pneumatic fluid power components
    2. Explain the need for symbol use in everyday fluid power work
    3. Draw commonly used pneumatic symbols
29. Measure pressures in pneumatic circuits
    1. Use the draft gauge (manometer)
    2. Explain how higher pressures are commonly measured
30. Relate volume and pressure
    1. Observe the effect of moving a ‘piston’ on the internal gas pressure of a tube or cylinder as a demonstration of force transmission through a fluid by Pascal’s law
    2. Differentiate gage pressure vs. absolute pressure
31. Measure Flow and Pressure Drop
    1. Show the behavior of fluid gas (or compressed air) during transmission from point of generation (or storage) to point of use
    2. Adjust flow and pressure to obtain desired results
32. Adjust a typical Pressure Switch Control
    1. Draw a pressure switch symbol
    2. Explain terms and definitions for pressure switch adjustments
    3. Set desired cut-in and cut-out pressures
33. Use Safety Relief Valves in pneumatic circuits
    1. Actuate the compressed air safety relief valve
    2. Set safety relief valve trip pressure
    3. Test a safety relief valve
34. Operate Pressure Regulators in pneumatic circuits
    1. Draw the schematic symbol for a vented type pressure regulator
    2. Explain pressure regulator behavior
    3. Describe the reaction of the pressure regulator during adjustment and under flow conditions
35. Use Directional Control Valves in pneumatic circuits
    1. Draw the schematic symbols for directional control valves
    2. Describe how directional control is achieved in pneumatic systems
    3. Explain the three major valve classifications
36. Relate force, area, and pressure in pneumatic cylinders
    1. Demonstrate use of the force triangle
    2. Calculate annular areas of cylinder pistons and rods
    3. Determine the behavior of different types of linear actuators
    4. Demonstrate force/area/pressure results of friction using linear actuators
37. Summarize Linear Actuator operation
    1. Analyze linear actuator behavior under load
    2. Explain linear actuator behavior as affected by
    3. Determine actuator air consumption
38. Use Rotary Actuators in pneumatic circuits
    1. Describe the CRAM
    2. List the advantages of continuous rotation air motors (CRAM).
    3. Define torque and how it applies to air motors
    4. Describe operation and performance characteristics
39. Control actuators with 3-Way Directional Control Valves
    1. Demonstrate 3-way DCV operation in several circuits with actuators
    2. Show manual valve metering
40. Control actuators with 4-Way Directional Control Valves
    1. Operate linear actuators with 4-way manual valve
    2. Describe common industrial applications for air bearings
    3. Show the behavior of equal bore and unequal bore cylinders operating in parallel
    4. Calculate air bearing lifting force
    5. Compare action of pressure regulator speed control to that of valve metering control
    6. Determine operating pressures and clearances on different work surfaces
    7. Show control of pilot operated directional control valve using 3-way valves
    8. Demonstrate limits of pilot pressure shifting
41. Relate air flow velocity to air pressure
    1. Demonstrate the relationship between air flow velocity and pressure
    2. Explain how the air flow velocity-pressure relationship makes pneumatic devices such as a lubricator function
42. Contrast air bearings and ground effect machines