how to measure CFM of compressor?

ndemge

Commander
Joined
Jul 15, 2002
Messages
2,644
Anyone here know how to measure the CFM of a compressor output?<br /><br />Have a 60 Gallon (8 Cubic feet) compressor, would like to get an idea of what it's real output is, and graph it for at what pressure it really starts working hard.
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: how to measure CFM of compressor?

A piston compressor will put OUT "about" 3 cfm per HP<br /><br />A screw compressor will put out "about" 4 cfm per HP <br /><br />With out the chart from that exact pump anything else is a WAG<br /><br />single stage/two stage/ect/all kinds of variables <br /><br />tommays
 

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: how to measure CFM of compressor?

Take a look at this:<br /><br /><br /> Calculating true rating <br /><br />I have no idea if it is accurate, but it sounds good . . .
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,241
Re: how to measure CFM of compressor?

CFM is a measure of the Compressor Head,+ it's drive motor.......<br /><br />Tank Capacity is Pretty Much,... Irrelevent......
 

Limited-Time

Vice Admiral
Joined
Mar 30, 2005
Messages
5,820
Re: how to measure CFM of compressor?

Cubic inch displacement of the pump per rev X pump rpm equals cubic inches per min. Cubic ipm divided by 1728 = CFM. hope that helps.
 

ndemge

Commander
Joined
Jul 15, 2002
Messages
2,644
Re: how to measure CFM of compressor?

QC.. THAT makes sense.<br /><br />The suggestions of going by the tags is not what I want, I want to know REAL WORLD what it puts out.<br /><br />Tank size does matter, cause that's how I calculate it, Stopwatch and timing between pressure readings will tell me output at give pressure.
 

dolluper

Captain
Joined
Jul 19, 2004
Messages
3,904
Re: how to measure CFM of compressor?

Think you should be more interested in the tools your trying to use with it,the ratings on the tank will tell you if the tool your using is suitable for that compressor.Bigger tanks mean you can use longer before recovery thats about it
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,241
Re: how to measure CFM of compressor?

Tank size does matter, cause that's how I calculate it, Stopwatch and timing between pressure readings will tell me output at give pressure.<br />
If that's Your case,......<br /><br />You can just Daisy Chain Several Tanks together..........<br />It Still doesn't Increase the CFM of the Compressor.........<br />You just get a longer Run Time to Fill it,+ alittle longer Run Time before the pump Kicks back In........<br />This is My added Storage.......<br />
airtank.jpg
<br /><br />I could link 100 of these tanks Together,+ I'll Still have the Same CFMs............... :rolleyes:
 

dolluper

Captain
Joined
Jul 19, 2004
Messages
3,904
Re: how to measure CFM of compressor?

Nice looking bomb Bondo....100 more what a boom that would make ....and when you accidently cut a lines, snakes flying around ....oh boy :D :D :D
 

ndemge

Commander
Joined
Jul 15, 2002
Messages
2,644
Re: how to measure CFM of compressor?

I know what my tools use, the duration of their use and the needed duty cycle. What I need to accuratly measure is the OUTPUT of my compressor.<br /><br />My compressor pump is 20 years old, it's had a replacement motor powering it, and one of the three cyclinders is a little bit weaker than the other 2. <br /><br />In my case, I will be pusing a pneumatic cylinder, and running a staple gun, with regulators, these two items will be given the exact same pressure all the time. I know how long we run both tools at a time, so Say I use 1,000 CFM of air in a given amount of time, and I know the output of my compressor, I then know how big the tank needs to be to overcome the heavy use time to for it to catch back up for the next run. <br /><br />I'm going to have 2 compressor's hooked together, if air pressure drops to a certain point, comrpessor #2 kicks on. I'd kinda like to know the math of what's going on than to just hook it all up and say yup, I think this will have enough capacity.<br /><br />
Originally posted by dolluper:<br /> Think you should be more interested in the tools your trying to use with it,the ratings on the tank will tell you if the tool your using is suitable for that compressor.Bigger tanks mean you can use longer before recovery thats about it
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: how to measure CFM of compressor?

We have a couple of high end Altas Copco screw compressors and a good dealer<br /><br />When they do a plant use evalutaion they put in a BIG inline CFM meter AFTER the tanks and watch what it says .<br /><br />At that point you can tune the system to meet your needs.<br /><br /> http://www.airometrix.com/ConsultSrvc.asp <br /><br />one of many testing companys but they all do it pretty much the same way<br /><br />tommays
 
Top