SKMT 220 - Hydraulics and Pneumatics I
Focuses on the operation and function of fluids, pumps, compressors, valves, cylinders, motors, filters, and other components used in the power and control of machine tools, construction and agricultural equipment. Uses algebraic formulas, charts, and graphic symbols for design and diagnosis of basic circuits. Credit may be earned in only one of SKMT 101, SKMT 220 or MT 220
Prerequisite(s): MATH LEVEL 4
Lecture Hours: 30 Lab Hours: 30
Meets MTA Requirement: None
Outcomes and Objectives 1. Solve fluid power problems using basic algebra
A. Calculate pressure given force and cross-sectional area, or diameter.
B. Calculate pressure given the head of the liquid above the point desired.
C. Calculate area of a circle given its diameter.
D. Calculate velocity of a cylinder given its diameter and flow rate.
E. Calculate torque on the shaft of a hydraulic motor given the pressure drop and volumetric displacement.
F. Calculate rpm of a hydraulic motor given its volumetric displacement and flow rate.
G. Calculate horsepower given pressure and flow rate.
H. Calculate output force and motion of a hydraulic jack, given input conditions.
I. Calculate efficiency, given input and output horsepower.
2. Demonstrate advanced principles of fluid power
A. Describe flow velocity and pressure conditions in a venturi.
B. Calculate flow velocity at an orifice in a tank given the head of liquid above it.
C. Describe pressure drop in a hydraulic circuit.
3. Demonstrate the importance of the fluid in a fluid power circuit
A. List at least 5 functions of the fluid.
B. Differentiate between compressibility and incompressibility of the fluid and how that affects performance.
C. Differentiate between viscosity and viscosity index of an oil.
D. Explain the symptoms of a hydraulic circuit with oil viscosity too high.
E. Explain the symptoms of a hydraulic circuit with oil viscosity too low.
F. List the factors that enhance oxidation, and explain its effect on performance.
G. Differentiate between the several fire-resistant fluids.
4. Explain the operation and list applications of hydraulic pumps
A. Explain how centrifugal pumps work.
B. Explain how gear pumps work.
C. Explain how vane pumps work.
D. Explain how piston pumps work.
E. Explain how screw and lobe pumps work.
F. Compare the pros and cons of each pump type.
G. Identify at least 2 industrial/commercial applications for each pump type.
5. Explain the operation and list applications of fluid power actuators
A. Explain how a single-acting cylinder works.
B. Explain how a double-acting cylinder works.
C. Explain how a gear motor works.
D. Explain how a vane motor works.
E. Explain how a piston motor works.
F. Explain how a gerotor motor works.
G. Explain how a vane rotary actuator works.
H. Explain how a rack/pinion rotary actuator works.
I. Identify at least 2 industrial/commercial applications for each actuator type.
6. Explain the operation and list applications of control valves
A. Explain the operation and differentiate between the 5 pressure control valves:
1. relief valve
2. unloading valve
3. sequence valve
4. counterbalance valve
5. pressure reducing valve
B. Identify where in a circuit each pressure control valve is normally placed. May be used in conjuction with the automation equipment.
C. Explain the operation and differentiate between the 4 directional control valves
1. one way
2. two way
3. three way
4. four way
D. Identify at least 5 different operators for directional control valves.
E. Compare 4-port and 5-port operation in directional control valves.
F. Compare sliding spool, shear seal, and poppet designs for directional control valves.
G. Explain the operations of simple flow control valves and pressure-compensated flow control valves.
H. Differentiate between a restrictor-inlet flow control and a bypass type.
I. Compare the 3 types of flow control circuits.
J. Explain the operation of a flapper-nozzle electrohydraulic servo valve.
K. Compare the operation and applications of electrohydraulic servo valves with proportional valves.
L. Explain the operation of a cartridge valve.
7. Explain the operation and application of several components typically found in a hydraulic circuit.
A. Explain the operation and use of an accumulator.
B. Explain the operation and use of an intensifier.
C. Explain the operation and use of a filter or strainer.
D. Explain the operation and use of a pressure gage and flow meter.
E. Explain the operation and use of a reservoir.
F. Explain the operation and use of a heat exchanger.
8. Explain the sequence of operations of a fluid power circuit.
A. Identify all graphic symbols in a fluid power circuit drawing.
B. Explain the sequence of operations, with different positions of the directional control valve, of the following types of circuits:
3. pressure reducing
5. hydrostatic transmission
6. meter-in and meter-out
9. Design a 3-cylinder/one-motor hydraulic sequence circuit commonly found in industrial applications.
A. Size all conductors in the circuit.
B. Recommend settings for all flow control valves.
C. Size all cylinders and the motor for proper force/torque and speed/rpm outputs.
D. Select proper directional control valves for the sequence.
E. Calculate the cycle time for each actuator in the sequence.
F. Recommend pump type and size.
G. Size the reservoir.
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