MAGICAL USE OF
‘PNEUMA’
IN
INDUSRIAL AUTOMATION
Maharshi Trivedi
5th semester MH 074,
Faculty Of Technology,
Dharmsinh Desai University,
Nadiad
Content
• Fluid Power System
• Brief History of PNEUMATICS
• Use and Advantages of PNEUMATICS System
• Basic Parts of any PNEUMATIC Circuits
• Air Generation and Distribution
• Air service Unit
• Filter
• Air Presser regulator
• Lubricator
• Flow Control Valve
• D.C. Valve
• Actuators
• Energy Conversion Cycle
• Some PNEUMATIC Circuits
Fluid Power System
• Fluid power systems are used in most of the modern machineries in order to
achieve the success in POWER TRANSMISSION, because sometimes the
mechanical drives are bulky and complicated.
• Fluid power system is the properly pressurized flow of air or liquid which is
used to actuate the mechanical means which is further used to achieve the
work.
• Thus, the fluid power energy is broadly classified as,
1) Fluid power energy with air medium
2) Fluid power energy with liquid medium
• So, Compressed air as the working medium = PNEUMATICS
Liquid as the working medium = HYDRAULICS
Brief History of PNEUMATICS
• The first man whom, we know with certainly to have
engaged himself with pneumatics i.e. the use of
compressed air as the working medium was the Greek
KTESIBIOS, he built a compressed air impulse
catapult(Shown in the fig is mechanical catapult).
• The term PNEUMA is described as the ambient Greek
and meant breath or heavy wind and also the soul in
philosophy.
• PNEUMATICS is derived from the word PNEUMA.
• The use of it is preferred when the need of automation
and rationality of optional sequences continued to
increase.
Use and Advantages of PNEUMATICS System
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USE:
For pneumatic tools for automation
of m/c tools (ex. CNC LATHE).
In mining industries and refineries
and also in aviation field.
In automation of food processing and
in chemical material handling.
In plastic manufacturing industries.
For building up the specific
atmosphere condition in textile
industries.
In spray painting.
ADVANTAGES:
• There will be no spark hazards in an
explosive atmosphere, as it is having
the air as the working medium and
the temperature conductance of air is
less then the liquid.
• Air is readily available and
compressed air can be stored in a
tank for instant use and a small
compressor can be used to fill the air
for intermittent use.
Basic Parts of any PNEUMATIC Circuits
• Air Compressor
• Service Unit:
F-R-L: Filter
Pressure Regulator
Lubricator
• Air distributor or Junction box
• Valves
• Cylinders
Air generation and distribution
• The main function of the air generation
and distribution system is to supply the
clean, dry air at the required pressure.
• Compressors are the air generation
units.(Classification of compressors are
shown in the fig.)
• Compressors compress the air and
supply it to the distribution system in
the factory and also it air service
unit(FRL unit) prepares the air and
delivers to the control unit.
(Compressors are not much discussed in
this ppt, the diff. types are used as per the
requirement)
Air Service Unit (FRL Unit)
• The air service unit is a
combination of:
1. Compressed air filter(With water
separator)
2. Compressed air regulator
3. Compressed air lubricator
• The main function of the service unit is
to provide the pneumatic system with a
well cleaned, lubricated and regulated
compressed air.
• The three units Filter-RegulatorLubricator together are termed as FRL
Unit or Service Unit.
Cont.…
• They are commonly fitted to each and
every pneumatic work station. After it is
determined whether fog-or-mist-type
lubrication is best suited for the
application, lubricators are selected
according to piping size.
Air Filter:
Air filters are used in a pneumatic system to
perform the following main functions:
To prevent entrance of solid contaminants
to the system.
To condense and remove the water vapour
that is present in the air passing through it,
in short it makes the air dry and clean.
To arrest any submicron particles that may
pose a problem in the system components.
Construction of Air Filter
• The main component of the filter is the
filter cartridge, is made of bronze or
brass. This helps to provide a random
zig-zag passage for the air to flow which
in turn, will arrest the solid particles.
• The water vapour gets condensed inside
the filter and collects at the bottom of
the filter bowl.
• At the bottom of the filter bowl there is
an on-off drain valve which could be
manually opened to drain off the
accumulated water and other solid
particles.(Construction is shown in fig.)
Oil free Filter Element
• If absolutely oil and moisture free air
is required, coalescent type(To form
whole as a unit means removal of oil
and moisture) of filter may be used.
The filter medium is made of metalwools which is kept compressed
inside a stainless steel shell and the
outer shell is made of some porous
material, e.g. ceramic or borosilicate
which can absorb the finer oilmolecules.
• The filtration medium is housed on a
seat made of stainless steel.
Air Pressure Regulator
• The main function of pressure
regulator valve is to regulate the in
coming pressure to the system so
that desired air pressure is capable of
flowing at a steady condition.
• The pressure regulation is achieved
by opening the poppet valve. This is
done by adjustable screw. It will
move the diaphragm. The pressure of
the flowing air will be directly
proportional to the compression of
the spring underneath the diaphragm.
Lubricator
• In most of the system the air is first
filtered, then regulated to the specific
pressure and made pass through the
lubricator in order to form mist of oil
and air to providing lubrication of the
mating components of the valve.
• Lubricator unit follow the principle of
venturimeter. According to the law, as
soon as compressed air flows into the
throttled zone of the pipe, a pressure
differential sets in. Due to this, the oil is
pushed up to the pipe when air is fed to
the oil reservoir through the pipe.
Diagram of construction of
Lubricator with symbol
Flow Control Valves
• Flow control valves are used in circuits to control the flow rate of the
compressed air from one part of the circuit to another.
• They regulate the amount of the compressed air passing through a valve by
means of a metering orifice.
• Examples are throttle valve and one-way flow control valve.
Throttle Valve(Restriction or needle valve)
• Throttle valve is used to control the
speed of pneumatic cylinders in both
direction of motion. So if the symbol
is not mentioned on the valve by
manufacturer, then also it can be
connected in both the direction due
to its geometry.
• It consists of an orifice whose crosssection can be controlled by an
externally adjustable needle.
One way Flow Control Valve
(Throttle relief Valve or Throttle check Valve)
• A one way flow control valve is used to control the flow of pneumatic
cylinders in one direction of motion only.
• The valve is a parallel arrangement of a throttle valve and a check valve.
• The check valve blocks the flow of air in one direction forcing the air to flow
through the controlled cross-section.
• In opposite direction the air flows freely through the opened check valve.
(Figure for this valve is shown in the next slide.)
Why it is one way Flow Control Valve???
Direction Control Valves
D.C. Valves
• Direction control valves are used to direct the flow of the pressurize fluid in the
desired directions.
• The main functions of these valves are to:
Start
Stop
Regulate the direction of air flow
• They can be actuated to assume different positions by various actuating mediums.
This results in corresponding connection or disruption of flow between various port
openings. The openings are termed ways or ports. The ways are designated by letters:
P=Compressor line port
R=Exhaust port | A and B=Working ports to cylinders or motors
Symbolic representation of
D.C. Valves
To represent valves in circuit diagram, symbols are used. Each
position in the symbol is denoted by squares. Two positions are
represented by two adjacent squares.
How to Understand the Symbols in the
circuits???
• A valve position is represented by a
square. Number of squares is equals
to the no. of distinct positions that
the valve can take up.
• Inside a square, the lines indicate the
flow and the arrows, the direction of
flow. Cut-offs of air flow are shown
by short traverse lines inside the
square.
• Connections to inlet and outlet ports
are drawn only to a connecting
position, i.e. neutral or initial
position.
Types of D.C. Valves
Poppet valves (or seat valves)
Slide valves (or spool valves)
• In a poppet valve, a simple valve
seat is used in conjunction with a
movable disc or ball to open or close
internal air passages.
• A poppet valve quickly opens up a
relatively large orifice in a short
travel to permit the full flow of air.
• In a slide valve, a spool moves
axially within the valve body to
control the direction of flow.
• A slide vane is especially used as a
final control element to handle the
power signal to an actuating device
because it is easy to shift the spool to
perform the required switching
function.
Working diagram of poppet and slide valve
Poppet valves (or seat valves)
Slide valves (or spool valves)
2/2 and 3/2 Way D.C. Valve(Normally Closed)
Check Valves
• A check valve permits the air flow in
one direction but stops it completely
in the opposite direction.
• It basically consists of a valve body,
movable ball or plate, it is biased by
a spring force.
• As soon as the pressure applied by
the compressed air becomes greater
then the spring force, it allows the air
to flow.
Actuators
• Actuators are used for
mechanical work which is
developed by the power of
compressed air:
• It is further classified as:
Linear actuators
Single acting cylinders
Double acting cylinders
Rotary actuators
Energy Conversion Cycle
Actual Valve Body
3/2 D.C. Valve (FESTO company)
D.C. Valve(Actuation by push button)
Some Pneumatics Circuits…
Working Circuit Video
(Triggering D/A Cylinder with Limit Switch)
PNEUMATIC Circuit in MATLAB!!!
My Experiment of Hydraulic circuits with MATLAB!!!
Thank You!!!