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Old 05-04-2009, 11:27 PM
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Greenbuggy Greenbuggy is offline
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Default How to convert CFM@PSI to CFM@different PSI?

So this is more a brain exercise than anything else, but I'm curious and unsure how the math works.

Say you have a Davey MC1A or similar scuba/paintball compressor, that produces a hypothetical 15 CFM @ 3500 PSI. Say you ran this thru a pressure regulator to produce 100 PSI. It would be my understanding that the air expands some going from 3500 PSI to 100 PSI. But assuming this is straight multiplication exercise would suggest that it produces 525 CFM @ 100 PSI which is clearly wrong.

Going by a HP estimate, that assumes about 4 CFM @ 100 PSI per HP for an efficient compressor, this compressor is capable of producing about 64 CFM @ 100 PSI. So whats the actual conversion? Some searching hasn't produced an answer yet.
Don't try this at home - UNLESS you live in a HOSPITAL!
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Old 05-05-2009, 01:01 AM
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OLD MAN OLD MAN is offline

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fifteen cfi at thirty five hundred pounds is a massive compressor.
You do the best you can with what you've got.
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Old 05-05-2009, 08:36 AM
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BBchevy396 BBchevy396 is offline
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Originally Posted by OLD MAN View Post
fifteen cfi at thirty five hundred pounds is a massive compressor.
I'd be willing to bet that it is 15CFH@3500psi, 15cfm would be a HUGE comp,,and require a massive amount of HP!
Or what? You'll release the dogs? Or the bees? Or the dogs with bees in their mouth and when they bark they shoot bees at you?
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Old 05-05-2009, 09:48 AM
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I suspect the specs mean 15 CFM of air at one atmosphere (on the intake side) can be compressed up to 3500 PSI at whatever volume on the output side.

Here's a little exercise in calculating volume:

EDIT: Possibly useful:
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Old 05-06-2009, 09:22 AM
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You could also play around with the information starting here:
Miller Thunderbolt XL AC/DC
Hobart Handler 190
Angle grinders,14" chop saw,Hobart medium duty O/A set
Some air tools,fair selection of hand tools,and other "stuff"

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