General considerations of Compressors

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If an instrument air system is tied  into another air source two Compressors (each with a separate power source) should be used for the system to avoid instrument shutdowns.

In comparing the installed cost of compressor for instrumentation air system the following observations is made.

(1)Reciprocating and centrifugal compressors are usually choice for instrumentation air units shsystem.

Rreciprocating units should be considered for rates below 1500 standard cubic feet per minute (scfm).

non lubricated models are relatively high,  both in installed cost and maintenance cost, but they provide clear, oil free instrument air and systems.

(2)For rates above 1500 standard cubic feet per minute(scfm) centrifugal compressor should be considered. installation and maintenance maintenance cost are lower and they are available in non lubricated models.

(3)The liquid piston compressor may be considered for oil free air quantities up to 500 standard cubic feet per minute(scfm) usually more economical than non lubricated Reciprocating Compressors.

(4)In the 100 to 500 standard cubic feet per minute (scfm) range, the rotary vane compressor has a low installation cost but non lubricated models are not available.

(5)In the 500 to 1500 standard cubic feet per minute(scfm) range, the screw type may be installed at a lower cost than centrifugal or reciprocating compressors. however, it is not oil fre.e



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