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8/7/2019 Compresses Air Table
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High efficiency filters
Replaceable element, typical filtration to 0.01um, oil to 0.01 mg/m3
Activated carbon filtersDesigned for oil removal to
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Correct Pipe Sizing
Pressure drop across distribution system should be less than 0.2 bar
Consider low friction aluminium or plastic piping systems
Points to consider when dealing with piping:
Horizontal lengths of distribution piping should be
sloped slightly downwards, with provision for
moisture drainage.
When designing a compressed air system, it is often a
good practice to add 30% to the expected air flow (to
add for future potential system expansion), and then
select the pipe diameter having the lowest pressure
The maximum design velocity for main distribution pipework is 6m/s
Forshort branch lines the velocity can be up to 15m/s
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The size of an air receiver can be calculated as follows:
reciprocating compressors
the rule of thumb for sizing a primary air receiver, has been from 1 gallon per cfm to 3 gallons per cfm of
compressor capacity
Primary air receivers
As a rule of thumb, for load/unload operated lubricated screw
compressors, the receiver volume should be 5 to 10 US gallons
(20-40 liters) per trim compressor scfm output. Other factors
come into play when sizing, such as the type of air compressor
method of capacity control and compressor starting delays.
Secondary receivers
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with a significant pressure differential across the system. The
alternative is to use a secondary storage receiver with the inlet
restricted by an orifice or needle valve.
100 cfm x 1 minute = 100 cubic feet
Pressure (psi) range = 20
Storage receiver required = 100 cubic feet 110/20
psi= 550 gallons (US)
This receiver could be filled over 10 minutes at a rate
of 10 cfm which would reduce the previous system
pressure differential by a factor of 100.
Facilities having large fluctuations in air demand, or havinginsufficient air pressure (usually at the end of the line), should
evaluate the need for one or more air receivers strategically
located in the air distribution system.
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1 gallon for each ACFM (Actual Cubic Feet per Minute), or
4 gallons per compressor hp (horse power)
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Resistance of Pipe Fittings in Equivalent Lengths (in metres)Compressed Air System
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Question: A 23 metre pipe with an inner diameter of 80 mm shall lead a flow of 140 l/s. Thepipe is routed with 8 elbows that all have a bend diameter equal to the inner diameter. How
great will the pressure drop across the pipe be if the absolute initial pressure is 8 bar(a)?
8 x 1.3 + 23 = 33.4 meters
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