1. ECT 459 Lecture 4 Pneumatics and Hydraulics

2. System Control Hydraulic and Pneumatic systems are controlled by the supply and control of fluid pressure, flow rate, and flow direction.

3. Applications Hydraulic and Pneumatic control systems are found in: • Construction Equipment • Factory Automation • Aircraft Flight Systems • Shipboard Controls • Military Vehicles • Farm Equipment

4. Measured Variables • Load Position • Load Speed • Load Pressure • Load Torque • Spool Displacement • Flow Rate • Pump Output Pressure • Pump Displacement • Pump Speed

5. Electronic Equivalents Tank Ground Pump Battery Pressure Gage Voltmeter Flow Meter Ammeter Relief Valve Voltage Regulator Directional Valve Switch Accumulator Capacitor Filter Low-Pass Filter Restrictor Resistor Check Valve Diode Hydraulic Motor Electric Motor

6. Additional Valves • Pump Side Relief Valves • Load Side Relief Valves • Cross-Over • Line-Tank • Check Valves

7. Filters • Suction Line • Pressure Line • Return Line • Case Drain • Kidney Loop

8. Control • Manual vs. Electronic • Fixed vs. Variable Displacement • Open vs. Closed Center • Parallel vs. Series • Open vs. Closed Circuit

9. Valve Types • Ports • 2, 3, 4 • Positions • 1, 2, 3, 4 • Center • Open, Closed • Actuation Method • Electrical, Mechanical, Pilot • Metering Element • Sliding Spool, Rotating Spool, Poppet (ball) • Control Purpose • Pressure, Flow, Both (proportional)

10. Actuation Methods • Mechanical Direct • Electrical Direct • Mechanical Pilot • Electrical Pilot

11. Valve Mounting • Cartridge Valves • Manifold Blocks

12. Hydraulic Sizing • Pressure • Flow Rate • Stroke Rate • Area • Torque