Fluid Power Application - 008 Pneumatics

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ydraulics & Pneumatics - KMD 2272

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Fluid PowerApplication(Pneumatics System)

Hydraulics & Pneumatics KMD3133

By,

Mohd Darnalis A.Rahman

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Learning ObjectivesUpon completing this chapter, students should be able to:

1. Apply the perfect gas laws to determine the interactions ofpressures, volume, and temperature of a gas.

2. Describe the purpose, construction, and operation ofcompressors.

3. Explain the purpose and operation of fluid conditioners,including filters, regulators, lubricators, mufflers, and air

dryers.4. Describe the purpose, construction, & operation of various

pneumatics pressure control valves, flow control valves, anddirectional control valves.

5. Discuss construction and operation of pneumatic cylinders.

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Introduction Pneumatics system utilize pressurized gases

to transmit & control power.

Medium air

Reasons safe, low-cost, & readily available.

Reasons of adopting pneumatics rather thanhydraulics is,1. Liquid weight2. Liquid viscosity3. No special reservoir needed (return air)4. Less leak5. Less expensive6. Compressed air can be stored


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Introduction However, compressibility of air makes it impossible

for the system to obtain precise movement &

velocities. Pneumatics system using compressor to supply air.

Typically of piston, vane or screw type.

Basically compressor increases the pressure byreducing the volume as described by the perfect gaslaw.

Air can be stored in a tank since air is compressibleand supplied using pipes to various locations. (suchas electrical system).

Air are then regulated, filtered, & treated whichprevents wear of the closely fitting moving parts ofpneumatic components

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Introduction Pneumatic working pressure


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Properties of Air

Air is actually a mixture of gases,

1%

21%

78%

Oxygen

Nitrogen

Other Gases (Carbon Dioxid e, Argon)

4%

96%

Air Water Vapou r

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Properties of Air

Out of 100% of air contains up to 4% of water

vapor depending on the humidity of air.

On sea level, atmosphere exert pressure of

14.7 psia (101 kPa absolute).

Air is not readily compressible but its volume

will vary to fill the vessel containing it.

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Properties of Air

Pressure & Altitude Relations


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Properties of Air

Absolute Pressure & Temperatures

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Properties of Air

The Perfect Gas Law

1. Boyles Law

2. Charles Law

3. Gay-Lussacs Law

4. General Gas Law

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Boyles Law

States that, If the temperature of gas held constant

The volume will change inversely with thepressure.


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Charles Law

States that, If the pressure of gas held constant

The volume will change proportional with thetemperature.

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Gay Lussacs Law

States that, If the volume of gas held constant

The pressure will change proportional with thetemperature.

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General Gas Law

States that, When, Boyles, Charles& Gay Lussacs are combined into a

single general gas law Defined, as having all three gas parameter (Pressure,

Temperature & Volume) None of them are held constant during process If either T, p, or V are held constant, the general gas law

reduces to Boyles, Charlesor Gay Lussacs law repectively.


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Compressors Compresses air or another type of gas a

low inlet pressure (usually atmospheric)to a higher desired pressure level.

Accomplished by reducing the volume ofthe gas.

Air compressors generally positive displacement units either

piston type.

Reciprocating piston type or the rotary screwor rotary vane types..

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PistonCompressors

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PistonCompressors


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Air Service Unit(Fluid Conditioner)

On delivery, on the outlet side; the air is then

flowed into a FRL unit to remove contaminants,regulate working pressures, and finally for

lubrication purpose.

Air from atmosphere contains moisture which

can lead to of lubrication problems. Air dryers

are needed to remove undesirable moisture.

Mufflers are used to reduce noise induced by

the exhaust of gas.

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Air Filter

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Air Regulator


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Lubricator

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FRL Unit

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Air Control Valves

Pressure regulators

Check valve

Shuttle valve

Directional valve

Flow control valve


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Pressure Regulator

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Check Valve

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Shuttle Valve


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Pneumatic Rotary Actuators

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Rotary Air Motors

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Thank you

Next class, pneumatics circuit diagram &

analysis.

Documents

Fluid Power Application - 008 Pneumatics