How do small ID connectors impact CFM/PSI?

by Bob
(Minnesota)

Air fittings

Air fittings

I am working on a basic 2 drop system for my 60 gallon single stage compressor (135psi, 12 CFM @ 90PSI, with a 1/2" output orifice). And I am getting hung up on pipe & hose sizing in relation to CFM & PSI.


1) How does having a 3/8" (.375") ID hose matter, when the factory 1/4" NPT fittings have an ID of ~.278"?

2) How is the CFM and PSI impacted by going from .375" to .278" then back to .375"?

I have read through a lot of content on your site this weekend, but still feel a bit uncertain about the impact of small orifices as the air moves between fittings (though I realize you have likely answered this even in something I have read already on your site). In my mind it seems like the small ID orifices would be a a bottleneck for air volume.

Thank you for all the time you put into sharing your vast knowledge of compressed air systems.

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Mar 12, 2017
Air flow and air line flow pretty much covered
by: Bill

http://www.about-air-compressors.com/estimating-pressure-drop.html , and many other flow related pages.

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