The document provides an overview of hydraulic and pneumatic systems, detailing components such as pumps, actuators, valves, and control elements. It introduces ISO symbols used in these systems for various components like pressure control and directional control valves. The content is designed for a course in control engineering under the mechanical engineering program.

1. Introduction to Hydraulics & Pneumatics
Dr. Biplov Kumar Roy
Assistant Professor (Mechanical Engineering)
Dhaka University of Engineering & Technology
DEGREE PROGRAM: B.Sc. in Mechanical Engineering
COURSE CODE: ME 4401
COURSE TITLE: Control Engineering

2. Structure of a hydrostatic drive
Aggregate Control
elements
Actuator
Valves,
determining the
path, pressure, flow
rate of the working
fluid
Elements doing
work
• Linear
• Rotational
• Swinging
Pump, motor
Fluid reservoir
Pressure relief
valve
Filter
Piping

3. 2005/2006 I. Hydraulic and Pneumatic Systems 3
A typical hydraulic system
1 – pump
2 – oil tank
3 – flow control valve
4 – pressure relief valve
5 – hydraulic cylinder
6 – directional control
valve
7 – throttle valve

4. Hydraulic power control

5. ISO symbols in Hydraulic & Pneumatics System

9. Pressure Control valve symbols
Pilot-Operated Relief Valve Pressure-Reducing Valve Unloading Valve
Sequence Valve
Counterbalance valves

10. Direction Control valve Symbol
Check valves Shuttle valves 3/2 way valve : 3ports and 2 position DC
5/2 Solenoid
Operated D.C.V.
4/2 Solenoid
Operated D.C.V.
4/3 Closed
centre D.C.V
4/3TandemCentre
4/3 Floating Neutral 4/3 Open Center 4/3 Regenerative Center

11. Flow Control valve Symbol
Variable Flow
Control Valve
Pressure compensated F.C.V. Press. & temp. Compensated F.C.V.
Flow control Valve with
integral Check Valve

12. Auxiliary Devices in FPS
Accumulators
Dead Weight Type Spring Loaded Type Gas Charged With
separator
Gas Charged
Without Separator
Press. Guage Flow meter Prime Mover Electric Motor
Cooler Heater Telescopic Cylinders

13. Pressure Relief Valve