1. Unit 6
Pneumatics and hydraulics
Technology 4

2. What do we know? Suggested questions and discussion starters:
– What is the name of the machine you can see in this picture?
– What is it doing?
– Do you think this machine uses a hydraulic or a pneumatic circuit?
– In what other kinds of machines are pneumatic and hydraulic circuits used in?

3. Pneumatic and hydraulic circuits
Which of these circuits is hydraulic, pneumatic and electric?
How are these circuits similar and how do they differ?

4. Compressors in pneumatic circuits
What function do compressors carry out in pneumatic circuits?
How are reciprocating and rotary compressors different?

5. Compressors in pneumatic circuits
What function do actuators carry out in pneumatic circuits?
Which actuator above is single-acting and which is double-acting?

6. Control elements in pneumatic circuits
What is the function of a valve in a pneumatic circuit?
With what type of cylinder do we normally use a 4/2 valve?

7. Control elements: shut-off valves
How do the above shut-off valves work?
Which valve carries out the logic function AND and which carries out OR?

8. Hydraulic circuits: pumps
What is the function of the pump in hydraulic circuits?
What two types of pumps can you see above?

9. What have we learned? Pneumatic and hydraulic circuits
Elements
Energy-generating elements , transport elements, actuators, control elements

10. What have we learned?
Pneumatic circuits are used in can-crushing machines, door open/close systems and pneumatic drills.
Provides the circuit with compressed air. There are two types: reciprocating compressors and rotary compressors.
Compressor
Usually made of steel or brass, soldered together or connected by steel or plastic connectors
Pipes
Elements of
pneumatic
circuits
Rotary actuators produce the rotating movement of an axle.
Actuators
Single-acting cylinders move a piston in one direction.
Reciprocating
actuators
Double-acting cylinders move the piston back and forward.
Directional control valves: 2/2 valves and 4/2 valves
Control elements
(valves)
Flow control valves
Shut-off valves: non-return valves, dual-pressure valves and shuttle valves
Protection and
maintenance elements
Air dryers, filters, lubricators, pressure relief valves, conditioning units, silencers

11. What have we learned?
Hydraulic circuits use a pump instead of a compressor. They can be used in platform lifts, forklift trucks and hydraulic presses.
Elements of
hydraulic
circuits
Pump
Gear pumps or screw pumps
Protection and maintenance elements
Filter, relief valve, and reservoir