1. Actuators and directional control valves
Module-3
Actuators and directional
control valves

2. Module Objectives
Differentiate between the main types of directional control valves.
Demonstrate the function and uses of 3/2 way valve, push button actuated.
Demonstrate the function and uses of 3/2 way valve, roller lever actuated.
Explain the function and uses of 5/2 way valve, selector valve.
Explain the function and uses of 5/2 way valve, pilot valves.
Explain the main types of pneumatic actuators.

3. Module Objectives cont’d…
Explain the function of the single acting cylinder and the
double acting cylinder.
8. Describe the main types of controlling single acting cylinder
and double acting cylinders
9. Draw the required circuit diagram as per the given
specifications.
10. Use the FluidSIM software to build and simulate a pneumatic circuits that contain DCV, single and double acting cylinders.
11. Safely use the pneumatic Festo trainers to build different circuits.
12. Build a pnueumatic circuit using DCV, single and double
acting cylinders on the Festo trainer and check their operation

4. Introduction to Directional Control Valves
Directional control valves are
devices which influence
the path taken by an air stream.
The directional control valve is
represented by two numbers.
The first number represents the
number of ports, and the second
number represents the number of
Positions.
DCV Ports and positions

5. 3/2 WAY A) 3/2 way DCV Push Button N/C B) 3/2 way DCV Push Button N/O
Types of Directional Control Valves
3/2 WAY
A) 3/2 way DCV Push Button N/C
B) 3/2 way DCV Push Button N/O
C) 3/2 way DCV Roller Lever N/C
D) 3/2 way DCV Selector

6. Types of Directional Control Valves
3/2 WAY
A) 3/2 way DCV-push button
- Normally Closed (N/C)
Function:
The DCV allows the air flow into different
paths from one or more sources.
Way of operation:
A 3/2-way valve has 3 ports and 2 switching
positions.
Normally closed means that compressed air
CANNOT flow initially through the valve.
When the pushbutton is actuated the valve is
opened, thus allowing the air to flow from port (1)
to port (2).
(a) pressure port (1) is blocked
(b) 3/2 way DCV push button (NC) (before actuation)
Fig. 3.3: 3/2 way DCV push
button (N/C) after actuation

7. 3/2 WAY Types of Directional Control Valves A) 3/2 way DCV-push button
- Normally Closed (N/C)
Un-actuated
In normally closed 3/2 way valve, a spring-loaded disk seal
blocks the air flow from the air supply port (1) to the working
port (2).
The working port (2) is connected
with exhaust port (3) as shown in Fig
on the right.
(b) 3/2 way DCV push button (NC) (before actuation

8. 3/2 WAY Types of Directional Control Valves A) 3/2 way DCV-push button
- Normally Closed (N/C)
Actuated
Allows the flow from port (1) to
port (2) and blocking the exhaust
port (3) .
ISO symbol of 3/2 way valve
normally closed (N/C) and
spring reset.
Picture of the valve.

9. 3/2 WAY Types of Directional Control Valves B) 3/2-DCV - push button
- Normally Open (N/O)
Way of operation:
Normally open means that compressed
air flows through the valve.
When the push button is actuated the valve is closed, thus stopping the air to flow from port (1) to port (2).
(a) 3/2 way directional
control valve N/O

10. 3/2 WAY Types of Directional Control Valves B) 3/2-DCV - push button
- Normally Open (N/O)
Un-actuated
In the normally open 3/2 way valve,
a spring loaded disk blocks exhaust port (3).
The air supply port (1) is connected to the
working port (2).
Actuated
Allows the flow from port (2) to port (3) and
blocking the supply air port (1).
Fig. (3.5.b) to the left shows the ISO symbol of 3/2 way valve
Normally open (N/O) and spring reset, and Fig. 5.5.c
shows the picture of the valve.
ISO symbol of 3/2 way
DCV push button (NO)
Picture of 3/2 way DCV
push button (N/O).

11. 3/2 WAY Types of Directional Control Valves
C) 3/2 Way-DCV- Roller Lever Valve
- Normally closed (N/C)
One of the most important types of valve actuation.
It is generally known as pneumatic limit switch.
Symbol and Construction
ISO symbol
Picture of the roller lever valve
Construction

12. 3/2 WAY Types of Directional Control Valves
C) 3/2 Way-DCV- Roller Lever Valve
- Normally closed (N/C)
Way of operation:
This valve is actuated by pressing the roller lever
e.g. by means of cylinder trip cam.
The valve is returned to the normal position via
return spring after releasing the roller lever.

13. 3/2 WAY Types of Directional Control Valves
D) 3/2 way, DCV selector valve
The way of operation of the selector valve is the
same as the 3/2 DCV push button.
The only difference that the selector valve is
keeping the last position active either it is
NO or NC.
Fig. 3.7 shows the picture and the ISO symbol
of the 3/2 way, selector valve.

14. 5/2 WAY Types of Directional Control Valves 1) 5/2 way Selector Valve
**** 5/2 way Directional Control Valve
This valve contains 5 ports and 2 positions.
The 5/2 DCV could be actuated manually or by using pressure actuation (single pilot and double pilot), or by electrical actuation (solenoid).
1) 5/2 way Selector Valve
2) 5/2 way Single Pilot
3) 5/2 way Double Pilot

15. 5/2 WAY Types of Directional Control Valves Before actuation
When the 5/2-way valve is not actuated,
the flow will be from port (1) to port (2)
while the exhaust will be from port (4)
to port (5)
After actuation
After operating the valve by any method,
the valve will be shifted to the other
position and in this case, the
flow will be from port (1) to port
(4) while the exhaust will be from
port (2) to port (3)
(a) Initial position (before actuation)
(b) Second position (after actuation)
ISO symbol of 5/2 way valve

16. 5/2 WAY Types of Directional Control Valves 1) 5/2 way selector valve
This valve is used for manual operation.
You can control the valve by selector switch.
It is used in simple applications.
The valve keeps the last position active as the 3/2 way selector.

17. 5/2 WAY Types of Directional Control Valves
B) 5/2 way single pilot valve
This valve is used for automatic operation
You can control the valve by a pneumatic signal and a spring
return.

18. 5/2 WAY Types of Directional Control Valves
C) 5/2 way double pilot valve
This valve is used for automatic operation
You can control the valve by two pneumatic signals
The valve keeps the last position after removing the applied
signal, and it is sometimes called memory valve.

19. Valve Actuators
The pneumatic directional control valves can be actuated (operated) in several ways such as follows: 1. Manual Actuators 2. Mechanical Actuators 3. Electrical Actuators

20. Valve Actuators
1. Manual actuators 2. Mechanical actuators 3. Electrical actuators 4.Electrical actuators
MANUAL
PUSH BUTTON
FOOT PEDAL
ROLLER
IDLE RETURN
ROLLER
SOLENOID
PNEUMATIC –
PRESSURE

21. Pneumatics Actuators
They are used to produce the required forces in the
pneumatic systems.
The pneumatic actuators are divided into:
Linear actuators
– Single acting cylinder
– Double acting cylinder
Rotary actuators
– Air motors

22. Single Acting Cylinder
Single acting cylinder is an output device.
Its function:
To convert the pressure energy to mechanical energy (linear force in one direction only).

23. Circuit Control for a Single Acting Cylinder
The piston rod of a single-acting cylinder is to advance when a push button is operated.
When the push button is released, the piston is to automatically return to the initial position.
A 3/2-way valve controls the single-acting cylinder.
The valve switches from the
initial position into the flow position, when the push-button actuator is pressed.

24. Double Acting Cylinder
Double acting cylinder is an output
device.
Its function to convert the pressure
energy to mechanical energy
(linear force and motion in two
directions). .
Note:
The force produced by the piston during the
advance stroke is greater than the force produced during the return stroke due to the area
difference between the two sides of the piston.

25. Circuit Control for a Double Acting Cylinder
The piston rod of a double-acting
cylinder is to advance when a 5/2
selector valve is operated and to return
to the initial position when the selector
switch is back to the normal position.
The double-acting cylinder can carry
out work in both directions of motion,
due to the full air supply pressure being
available for extension and retraction.
A direct control circuit of a double acting
cylinder is shown in Fig to the left.

26. Applications of a double acting cylinder include
1. Opening and closing doors 2. Taking items off conveyor belts and putting items on conveyor belts. 3. Lifting and moving packages around. 4. Presses and punches.

27. SINGLE ACTING CYLINDER DOUBLE ACTING CYLINDER
Comparison between single and double acting cylinder
SERIAL
SINGLE ACTING CYLINDER
DOUBLE ACTING CYLINDER 1
It has one port
It has 2 ports 2
It has a spring.
It has no spring 3
It exerts force in one
direction only.
It exerts force in 2 directions
(forward and backward) 4
It uses compressed air in
the forward stroke while
the return stroke is
achieved by the spring.
It uses compressed air in both forward and backward strokes

28. How to control pneumatic cylinders?
There are two ways to control pneumatic cylinders: 1- Direct control 2- Indirect control

29. Direct Control of a Pneumatic Cylinder
The simplest level of control for the single or double
acting cylinder involves direct control signals.
The cylinder is actuated directly via a manually or mechanically actuated valve, without any intermediate a switching of additional directional control valves.
If the port sizes and the flow values of the valve are too
large, the operating forces required may be too great for
direct manual operation.
Reference values for limits of direct cylinder control:
Cylinder with piston diameter smaller than 40 mm
Valves with connection sizes smaller than 1/4"

30. Indirect Control of a Pneumatic Cylinder
Cylinders with a large piston diameter have a high air requirement.
A control element with high nominal flow rate must be used to actuate these.
If the force should prove too high for a manual actuation of the valve, then an indirect actuation should be constructed, whereby a signal is generated via a second smaller valve, which will provide the force necessary to switch the control element.

31. Safety in the Pneumatics Lab
The following safety precautions should be strictly followed in the pneumatics lab. 1. Wear the safety gear before starting any practical work on the trainer. 2. The working pressure shouldn’t exceed 6 bar, that could be achieved by adjusting the pressure regulator in the air service unit to 6 bar. 3. Securely plug in pneumatic devices. 4. Keep piston rod travel free. 5. Check all connections before connecting the compressed air. 6. Do not exceed the maximum pressure. 7. Do not completely unscrew the regulating screw. 8. Tighten each locknut after setting the regulating screw. 9. Never tighten the regulating screw with force. 10. Never operate roller by hands. 11. Connect the compressed air supply only when you complete all connections.

32. Practical Tasks 1 & 2

33. References 2- Festo manuals and textbook TP101
For further reading, you can use the following links: 1- 2- 3-
11. Supplementary recourses
1. Pneumatics video from Festo.
2. FluidSIM software.
12. References
1- Festo manuals and workbook TP101
2- Festo manuals and textbook TP101

34. Classwork
Do the worksheet at the end of module 3 in class

35. Home work
Don’t forget to submit homework 3 next class