This document discusses the design of pneumatic circuits. It begins by introducing pneumatics as the transmission of power through compressed air. The basic components of a pneumatic system are then outlined, including compressors, filters, control valves, and actuators. Common pneumatic circuits like single and double acting cylinders are described. The document concludes by discussing considerations for pneumatic circuit design and some applications of pneumatic systems.

1. DESIGNOF
PNEUMATICCIRCUITS
PM MOHAMED ABUBACKER SIDDIQUE
2020AMM012
DEPT. OF AEROSPACE AND APPLIED MECHANICS, MECHANICS OF FLUIDS
26-06-2021 Design of Pneumatic circuits 1

2. Contents
 Introduction
 Pneumatics system
 Components of a Pneumatic system
 Pneumatic circuits and Design considerations
 Applications
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3. Introduction
 Most industrial processes require objects or substances to be
moved from one location to another, or a force to be applied to
hold, shape or compress a product. Such activities are performed
by prime movers, the workhorses of manufacturing industries.
 The prime movers works with three mode of transmission of
Electrical power, Mechanical power, Fluid power.
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Mechanical Power
Transmission
Electrical Power
Transmission
Fluid Power
Transmission

4. Pneumatics
system
 Pneumatic is a transmission of power through gas or air (Fluid
Power).
 Pneumatic technology deals with the study of behavior and
applications of compressed air in our daily life in general and
manufacturing automation in particular.
 Pneumatic systems use air as the medium which is abundantly
available and can be exhausted into the atmosphere after completion
of the assigned task.
 Some of the advantages of pneumatic system are
 Very cheap (air source)
 Can transfer power even in
long distance.
 No effect on higher temperature
 Flexibility in control
 Very fast response and movement
 No air return
 Clean working area
 Easy to setup (build circuit)
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5. Components
of a Pneumatic
system
 Basic components of a Pneumatic system
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6. Contd..
 Air filters: These are used to filter out the contaminants from the air.
 Compressor: Compressed air is generated by using air compressors.
Air compressors are either diesel or electrically operated. Based on
the requirement of compressed air, suitable capacity compressors
may be used.
 Air cooler: During compression operation, air temperature increases.
Therefore coolers are used to reduce the temperature of the
compressed air.
 Dryer: The water vapor or moisture in the air is separated from the air
by using a dryer.
 Control Valves: Control valves are used to regulate, control and
monitor for control of direction flow, pressure etc.
 Air Actuator: Air cylinders and motors are used to obtain the required
movements of mechanical elements of pneumatic system.
 Electric Motor: Transforms electrical energy into mechanical energy.
It is used to drive the compressor.
 Receiver tank: The compressed air coming from the compressor is
stored in the air receiver.
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7. Pneumatic
circuits and
Design
considerations
 The following are the symbolic representations of the components
of a basic pneumatic system
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8. Contd..
 The standard structure of pneumatic system has the following
view,
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9. Contd..
 Single acting pneumatic cylinder circuit design,
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10. Contd..
 Working
An electric motor is used to supply compressed air.
An air receiver accumulates and stores air for uninterrupted supply.
Compressed air form the receiver is then passed through the FRL
(Filter Regulator Lubricator) unit which filters the air of
contamination, regulates contestant flow of air as well as lubricates
the oil and removes moisture.
Directional control is provided by a 3/2 solenoid valve which
regulated the flow of air from the input to the cylinder as well as
from the cylinder to the exhaust.
 A muffler may be used for silencing the exhaust air.
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11. Contd..
 Basic circuits:
A basic circuit is a pneumatic circuit designed to perform basic
tasks, such as flow amplification, signal inversion, memory, delay,
single acting cylinder control, double acting cylinder control, etc.
Flow amplification
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 Cylinders with a large capacity
require a larger flow of air, which
can be hazardous to users.
 It is unsafe to manually operate
pneumatic directional control valves
with large flow capacity.
 Instead we should first operate
manually a small control valve and
use it to operate the pneumatic
control system with large flow
capacity

12. Contd..
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Signal inversion
 The directional control valves
can be switched.
 When operating control valve
1, control valve 2 will stop
producing pressure output.
 When control valve 1 ceases
operation and is restored to its
original position, control valve
2 will resume its output.
 Therefore, at any given time,
the pressure output of control
valve 1 is the exact opposite of
that of control valve 2.

13. Contd..
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Memory function
 The directional control valves
can be switched.
 When operating control valve
1, control valve 2 will stop
producing pressure output.
 When control valve 1 ceases
operation and is restored to its
original position, control valve
2 will resume its output.
 Therefore, at any given time,
the pressure output of control
valve 1 is the exact opposite of
that of control valve 2.

14. Contd..
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Delay function
 A pneumatic delay circuit can
delay the operating time of
the next control valve.
 Its principle of operation
involves the use of an orifice to
slow down the flow of air and
control the time of pneumatic
operation.
 Delay functions can be divided
into two classes: ON-signal
delay and OFF-signal delay.

15. Contd..
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Logic functions
OR Function  When either of the DC valve is
operated the circuit is active
and the cylinder will work.
 This is achieved using a
Shuttle valve.
 A shuttle wave allows flow to
pass through in one direction
where is the pressure of the
fluid is applied.
1 2
1 2
ON
OFF
 
 
1
2
In Out
1 1 ; 1 0
2 1 ; 2 0
 
 

16. Contd..
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Logic functions
AND Function
 The circuit will be on when
both the DC valves are on. And
the circuit will be off when
both the DC valves are off.
1 2
1 2
ON
OFF
 
 
1
2
In Out
1 1 ; 1 0
2 1 ; 2 0
 
 

17. Contd..
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Logic functions
NOT Function  NOT functions are inverse
control functions.
 In order to hold or lock an
operating conveyor or a similar
machine, the cylinder must be
locked until a signal for
cancelling the lock is received.
 Therefore, the signal for
cancelling the lock should be
operated by a normally open
type control valve.
 However, to cancel the lock, the
same signal must also cancel the
locks on other devices, like the
indication signal 3.
 The normally closed type
control valve 1 can be used to
cut off the normally open type
control valve 2 and achieve the
goal of changing the signal.
1 2
1 2
ON
OFF
 
 
1
2
In Out
1 1 ; 1 0
2 1 ; 2 0
 
 

18. Contd..
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Double/Multi acting circuits
 The only difference between a
single acting cylinder and a
double acting cylinder is that a
double acting cylinder uses a 5/2
directional control valve instead
of a 3/2 directional control valve.
 Usually, when a double acting
cylinder is not operated, outlet
‘B’ and inlet ‘P’ will be
connected.
 In this circuit, whenever the
operation button is pushed
manually, the double acting
cylinder will move back and
forth once.
 Many cylinders can be operated
in this manner with sequencing
valves.

19. Contd..
 The major design consideration in a pneumatic system are as
follows
Safety of operation
Performance of desired function
Efficiency of operation
Leakage and frictional losses
Costs.
 Good design practices:
Ensures proper plant air supply pressure
Use a manual, lockable air dump valve
Use a filter regulator
Use an electric soft-start valve
Don’t oversize the cylinder
Use flow controls
Use mufflers for noise control
Use lubricators only if necessary
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20. Applications
 Pneumatic systems has a wide range of applications in our day to
day life. Some of the important once are as follows.
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Industries Material Handlings General applications
Manufacturing industries Clamping Packaging
Automotive industries Shifting Filing
Food processing industries Positioning Metering
Textile industries Orienting Locking
Branching of material flow Driving of axes
Door control

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