ECT 459 Lecture 4 Pneumatics and Hydraulics System Contro

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