Air or Gas Compressor

7/24/2019 Air or Gas Compressor

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Air or Compressors

Lecture # 23-24

Mujahid Mehdi Abro IndusUniversity


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Air or Gas compressors

Compressor is a machineused to compressed air orgas to a fnal pressureexceeding 24!2" $a

%a%e.

&'

Compressor is used toincrease the pressure o air

rom low pressure to highpressure by using someexternal energy.


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U()( &* C&M$')(()+AI'

Operation o small engines

Pneumatic tools

Industrial cleaning by air blast

Tire ination Paint Spraying

anuacture o plastics and otherindustrial products

Textile Industry

!ot o use in wea"ing machine

Compressors are used in wet#processingdepartment


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Main Components in

Compressed Air Systems

Intake air filters

Inter-stage coolers

Air dryers

Moisture drain traps

Receivers


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Compressed air systems consist o ollowingma$or components%

Inta,e Air *iters that pre"ent dust romentering a compressor. &ust causes stic'ing"al"es( scoured cylinders( excessi"e wear

etc.

Inter-sta%e Cooers that reduce thetemperature o the air beore it enters the

next stage to reduce the wor' ocompression and increase e)ciency. Theyare normally water#cooled.


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Air-dryers that remo"e the remainingtraces o moisture ater ater#cooler ase*uipment has to be relati"ely ree o anymoisture.

Moisture drain traps that are used orremo"al o moisture in the compressed air.

These traps resemble steam traps. +arious

types o traps used are manual drain coc's(timer based , automatic drain "al"es etc.

'eceivers that are pro"ided as storage

and smoothening pulsating air output #


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-ey%#.'/ /on 0eturn +al"e 1 a one way "al"e(/ Saety "al"e. The fnal saety "al"e is usually set 234 abo"ethe cylinder maximum wor'ing pressure$M/ Pressure maintaining "al"e 1 5 crucial part o the fltrationsystem usually set to release pressure between 263#273 bars.


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Types of Compressors

Type of

compressor

Positive

displacement

ReciprocatingRotary

Dynamic

Centrifugal Axial


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01$)( &* C&M$')((&'(I0 ')($)C0 0& U(AG)

Centrifugal Compressors %

8or low pressure and high capacity application

Rotary Compressors %

8or medium pressure and low capacityapplication

Reciprocating Compressors %

8or high pressure and low capacity application


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Reciprocating Compressor

In a reciprocatingcompressor, a volume of air

is drawn into a cylinder, it is

trapped, and compressed by

piston and then dischargedinto the discharge line. The

cylinder valves control the

flow of air through the

cylinder; these valves act as

check valves.


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There are two types o reciprocatingcompressor

Single 1 5cting compressor

It is a compressor that has one discharge perre"olution o cran'shat.

&ouble 1 5cting Compressor

It is a compressor that completes two

discharge stro'es per re"olutions o cran'shat.ost hea" #dut com ressors are double

Types of Reciprocating

Compressors


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Parts of Reciprocating Compressor


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orking of Reciprocating Compressor

!Disc"arge#


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orking of Reciprocating Compressor

!Disc"arge#


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orking of Dou$le Acting Reciprocating

Compressor

(ta%e

(ta%e3

(ta%e2


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Advantage of Dou$le Acting

Compressor

0eduction in power re*uired to dri"e thecompressor.

9etter mechanical balance o the whole unit

and uniorm tor*ue. Increase in "olumetric e)ciency.

0educed lea'age loss.

!ess di)culty in lubrication due to low wor'ingtemperature.

!ighter cylinders can be used.

Cheaper materials can be used or


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Rotors instead of pistons% continuousdisc"arge

&enefits% lo' cost( compact( lo' 'eig"t(

easy to maintain

Types

)o$e compressor

Scre' compressor

Rotary vane * Slide vane

Rotary Compressor


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Centrifugal Compressor

Centrifugal compressorsaccelerates the velocity of the

gases (increases kinetic energy)

which is then converted into

pressure as the air flow leavesthe volute and enters the

discharge pipe.

sually operate at speeds !

",### rpm.

$eliver much higher flow rates

than positive displacement

compressors


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Impellers( +anes( +olutes(Suction :yes( &ischargelines( &i;user Plates(

Seals( Shat( Casing

Suction +ane Tips Parto the impeller "ane that

comes into contact withair frst.

&ischarge +ane Tips

Part o the impeller "ane

asic Components

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Air or Gas Compressor