Pneumatics

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Pneumatics
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What is pneumatics?

• Its the technology that deals with the study of
  the behavior and application of the compressed
  air.
• It is also a fluid power system which uses air as
  a power transmitting medium.
• Most industrial pneumatic applications use
  pressures of about 5 to 6 bars

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Components of Pneumatic system

• Air compressor
• FRL unit
• Direction control valves
• Logical valves
• Timers
• Flow control valves
• Cylinders
• Motors..

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Applications

• Compressed air systems are generally used to
  provide controlled motion using cylinder
  actuators for linear motion and rotary actuators
  rotary motion.. 
• Pneumatics can be used at all places where
  hydraulic is used with the following condition
• Pressure and accuracy demanded are within the
  limitations of pneumatics

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Applications

• Power tools

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• Pneumatic drills

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• Pneumatic guns

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• Nut runners

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• Pneumatic clamps

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• Pneumatic Caulking tool

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• Pneumatic grippers

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Air Operated Hoists
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Polisher for soft stones
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Grinder
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• Air brakes of automobiles
• Railway coaches
• Wagons
• Pneumatic hammers
• Pneumatic conveyors
• Doors opening and closing
• Assembly lines
• Stamping machines
• Embossing machines
• Lifting Molten metal from furnace
• Pneumatic bending machines
• Pneumatic punching machines

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• Glass industries for material transport using
  vacuum grippers
• Bottle manufacturing plants
• Automatic packing machines
• Wipers using air motors
• Food processing plants
• Paint Spray Guns
• Air driven Hoists
• Pick and Place units
• Pneumatic transfer systems are employed in many
  industries to move powders and pellets

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• Why are pneumatic power systems so popular in
  such a wide range of work functions?
• Electronic systems certainly have a much faster
  response to control signals. Mechanical systems
  can be more economical. Hydraulic systems can be
  more powerful.

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Pros

• A basic advantage is their high efficiency
• For example, a relatively small compressor can
  fill a large storage tank to meet intermittent
  high demands for compressed air. Unlike hydraulic
  systems, no return lines are required
• Wide availability of air
• Compressibility of air
• Easy to transport

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• High reliability, mainly because of fewer moving
  parts and fire-proof and explosion characteristic
  of the medium
• Compactness
• Forces, torques and speeds readily variable over
  a widely useful range
• Easy control and coordination with other
  machine/system functions
• Easy maintenance
• Low cost compared to hydraulics

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• Can also be used under wet conditions with no
  electrical shock hazard
• Remote controlling if the unit is provided with
  its own drive motor, then virtually the entire
  system can be installed at any pointeven away
  from the machineas long as that point can be
  reached by a hose, pipe, or tube to transmit the
  pneumatic power.

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• Light weight system The working fluid is very
  light in weight so supply hoses are not heavy.
• Leakage is not a big problem
• Quick response

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Cons

• One is the need for a compressor and for
  distribution lines, compared to the convenience
  of plugging an electric motor into an existing
  electric system.
• Can not provide high pressure and accuracy
• High cost compared to mechanical and electrical
  system

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Gas Laws

• Though air is mixture of several gases, it
  behaves like a perfect or an ideal gas with very
  insignificant deviation from the ideal gas. So
  ideal gas laws are applicable to air

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• pressure p versus volume V
• temperature T versus volume V
• volume V versus amount n

.
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Boyles Law

• pressure volume relationship
• (temperature is constant)

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p 8 1/V
p const/V
p V const
p2 V2 const
p1 V1 const
p1 V1 p2 V2
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Charless Law

• At constant pressure, the volume of a given mass
  of an ideal gas increases or decreases by the
  same factor as its temperature (in kelvins)
  increases or decreases.

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V 8 T
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V 8 T
V const T
V/T const
V2 / T2 const
V1 / T1 const
V1 / T1 V2 / T2
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Avogadros Law
amount volume relationship (pressure and
temperature are constant)
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n 8 V
n const V
n/V const
n2 / V2 const
n1 / V1 const
n1 / V1 n2 / V2
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IDEAL GAS EQUATION
(1) p 8 1/V
V 8 1/p
(2) V 8 T
V 8 T
(3) n 8 V
V 8 n
V 8 T n / p
p V const n T
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p V const n T
p V R n T
p V m R T
R 8.314 J / mol / K