Pneumatics involves the controlled use of compressed air. When used correctly, compressed air is a s

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pneumatics
Pneumatics involves the controlled use of
compressed air. When used correctly, compressed
air is a safe form of stored (potential) energy.
It is put to a wide variety of uses such as
dentists drills, automatic doors, brakes on
lorries and hammer drills used at roadwork's.
In school projects
Roadwork drills
Dentist drills
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pneumatics- safety
Safety is of the utmost importance when handling
compressed air.
If compressed air enters the body it can kill.

• Never use your finger to detect if compressed air
  is present, and always keep compressed air away
  from your eyes, nose, mouth etc.

• When connecting pneumatic circuits, make sure
  that all connections are secure before finally
  connecting your circuit to the compressed air
  supply

• As well as direct danger from the compressed air,
  pneumatic pistons can move quickly and with a
  great deal of force, so always be careful to keep
  fingers etc. away from live pneumatic systems.

• Always work at a sensible air pressure, 2.5 bar
  (250, 000 N/M2

• Never blow air at anyone

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the basics
Pneumatic systems typically involve a source of
compressed air being controlled by valves and
causing output devices such as cylinders to
operate in a controlled way. The compressed air
is typically obtained from a COMPRESSOR, which is
usually driven by an electric motor or an
internal combustion engine.. Air is routed
through pipes to VALVES which control the routing
of the compressed air. Valves may be operated by
a range of ACTUATORS including levers, rollers
and solenoids. The air is then passed on to
cylinders which convert the energy in the
compressed air into linear motion and do useful
work. Finally, the used compressed air is
released into the atmosphere as EXHAUST. During
the course of the above, the compressed air may
pass through filters and lubricators to clean the
air and add lubricant to ensure that equipment
has a long and reliable working life. It may also
pass through regulators to control the amount of
pressure available in the system.
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component symbols
Double Acting Cylinder
Single Acting Cylinder
3 Port Valve
5 Port valve
Flow control valve
Shuttle valve
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valves- 3pv types of control
Typical 3Port valve
Push -button
Plunger
Pilot pressure
Roller operated
This is the typical three port valve operation,
being a Push Button with spring return.
Lever operated
Pedal operated
Spring return
Solenoid
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valves- 3pv / 5pv
Valves control the switching and routing of the
air in a pneumatic system. From studying the
operation of cylinders, you may have already
worked out that valves not only have to control
the flow of compressed air, they also have to
control the flow of exhaust air to the
atmosphere. There are two main types of valves
used in pneumatic switching circuits, the 3/2
valve and the 5/2 valve.
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valves- 3pv
The 3/2 valve is used to control items such as
single acting cylinders which have a single
input. The input to the cylinder is connected to
port 2, the air supply to port 1 and port 3 is
allowed to exhaust to atmosphere.The number 3
signifies that the valve has three ports, whilst
the number 2 signifies that the valve has 2
directions or states.
PRESSURE OR MECHANICAL FORCE
AIR PRESSURE SOURCE
PRESSURE OR MECHANICAL FORCE
EXHAUST AIR RETURN
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valves- 5pv
The 5/2 valve is used to control items such as
double acting cylinders which have two inputs.
The inputs to the cylinder are connected to ports
2 and 4, the air supply to port 1. Ports 3 and 5
are allowed to exhaust to atmosphere.The number
5 signifies that the valve has five ports, whilst
the number 2 signifies that the valve has 2
directions or states.
PRESSURE OR MECHANICAL FORCE
AIR PRESSURE SOURCE
EXHAUST AIR RETURN
PRESSURE OR MECHANICAL FORCE
AIR PRESSURE SOURCE
EXHAUST AIR RETURN
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valves- flow control valve / shuttle valve
Inserting a regulator in the exhaust circuit of a
cylinder will slow down the movement of the
cylinder as the exhaust air has to work hard to
escape through the regulator. Thus a flow control
valve regulates the speed of the piston.
Flow control valve
A shuttle valve enables a Or circuit to be used
within in pneumatics. The valve enables two
inputs to be joined together with either one
having the ability to control a output. This
works by a ball which is blown to either side
when a 3pv is operated. When the ball moves
position it blocks the other inlet and the air
can only travel through the output valve.
Shuttle valve
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cylinders - sac / dac
Cylinders convert the energy in the compressed
air into linear motion. The air enters the
cylinder and pushes a piston from one end of the
cylinder to the other. There are two main types
of cylinder - single acting and double acting. A
single acting cylinder has only one air
connection, whilst a double acting has two.
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cylinders - sac
In a single acting cylinder, the piston is forced
out by the pressure of the air. When the air
supply is removed and the air inside the cylinder
is allowed to escape, the piston moves back,
driven by the force of a spring. By restricting
the escaping air (exhaust), it is possible to
slow down the return movement of the piston.
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cylinders - dac
The double acting cylinder has two air
connections. When compressed air is applied to
one connector and the other connector is allowed
to exhaust to atmosphere (i.e.. the air is
allowed to escape freely), the piston is driven
to one end of the cylinder. When air is then
applied to the second connector and the first is
allowed to exhaust to atmosphere, the piston is
driven back. This type of cylinder gives greater
power on the return stroke than the single acting
cylinder, and also ensures that the piston is
effectively locked in position at both ends of
its stroke.