1. Valves Non-return valves Flow control valves Pressure control valves
Directional control valves
Non-return valves
Flow control valves
Pressure control valves
Shut-off valves

2. Directional control valves
Directional control valves are devices which influence the path taken by an air stream. Normally this involves one or all of the following: opening the passage of air and directing it to particular air lines, cancelling air signals as required by blocking their passage and/or relieving the air to atmosphere via an exhaust port.

3. Directional control valves
The valve is described by:
Number of ports or openings (ways): 2-way, 3-way, way, etc.
Number of positions: 2 positions, 3 positions, etc.
Methods of actuation of the valve: manually actuated, mechanically actuated, pneumatically actuated, electrically actuated.
Methods of return actuation: Spring return, air return, etc.

4. Directional control valves: symbol development

6. numbering system used to designate directional control valves

7. Actuation of valves

8. Actuation of valves

9. 3/2-way valve,normally closed,ball seat

10. 3/2-way valve: disc seat normally closed,

11. 3/2-way valve: disc seat normally open,

12. 3/2-way valve single pilot, normally closed, with spring return,

13. Pilot valve: left unactuated, right actuated

14. 3/2-way roller lever valve, internal pilot,
Normally closed
Normally open

15. 4/2-way valve, disc seat,
unactuated
actuated

16. 4/3-way plate slide valve, mid-position closed

17. 5/2-way valve: longitudinal slide principle

18. 5/2-way double pilot valve, suspended disc seat,
flow from 1 to 2
flow from 1 to 4

19. 5/3-way valve, neutral position variations

20. Non-return valve and its derivatives
Check valve
Shuttle valve
Dual-pressure valve
Quick exhaust valve

21. Non-return valve

22. Dual pressure valve: logic AND function

23. Shuttle valve: logic OR function

24. Quick exhaust valve: flow from 1 to 2
Quick-exhaust valves are used to increase the piston speed of cylinders by reducing the resistance to flow, the
air is expelled to atmosphere close to the cylinder via a large orifice
opening

25. Flow control valves

26. Throttle valve
Flow control valves influence the volumetric flow of the compressed air
in both directions
normally adjustable
used for speed control of cylinders

27. One-way flow control valve
air flow is throttled in one direction only
A check valve blocks the flow of air in the bypass

28. Fundamentally, there are two types of throttling circuits for double-acting
cylinders:
Supply air throttling
Exhaust air throttling

29. Mechanically adjustable one-way flow control valve

30. Pressure valves They are divided into the three groups:
Pressure regulating valve
Pressure sequence valve
Pressure limiting valve

31. Pressure regulating valve

32. Adjustable pressure sequence valve

33. Pressure relief valves Pressure limiting valve
Pressure relief valves protect the compressor and
components by setting the maximum sys tem pressure within safe working limits.

34. Combinational valves
Components of different control groups can be combined into the body of one unit with the features, characteristics and construction of a combination of valves, such as:.
Time delay valves: for the delay of signals
Two-hand start unit
Pulse generator
Stepper modules
Memory modules

35. Time delay valve: normally closed

36. Time delay valve: normally open

37. Time response of circuits
with time delay valves

38. Time response of circuits with time delay valves

39. Time response of circuits with time delay valves

40. Pulse generator, Stepper modules Memory modules
which incorporate directional control
valve functions and logic elements to perform a combined processing
task.
This reduces size, cost and complexity of the system